Thursday, March 30, 2006

Lousy Performance, High Hardware Interrupt Usage

My system has been dog doo slow since I did a reinstall a couple weeks back.  Process Explorer was showing some outrageous hardware interrupt rates, on occasion as high as 50% and regularly at 20%.
I’d let it roll for a couple weeks simply because it was low on my frustration list and I was trying to roll through other things.  It finally pissed me off enough tonight that I spent some time nailing it down.  Turns out ATA/IDE controllers will often revert back to PIO mode instead of Ultra-DMA.  (MS KB article on the problem here.)
Check the problem by examining the controller’s Primary and Secondary IDE settings: Device Manager -> IDE ATA/ATAPI controllers -> Primary or Secondary IDE Channel -> Properties -> Advanced Settings.  Look at the Current Transfer Mode field.  If it’s “PIO” then it’s a FUBAR PITA and you’ll need to uninstall the driver, reboot and let XP do its magic reinstall. 
Sucky, but fixable.  Now I’ve got my shiny system back shiny again.
Now Playing: Olu Dara — In The World: From Natchez to New York.  Wow, jazzy/bluesy/folksy goodness.  Amazing clarity, terrific vocals, killer guitar and harmonies.

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Anonymous Anonymous said...

Thanks very much. Was pulling my hair out with the same problem and now its sorted.

12/14/2006 1:51 PM  
Anonymous Anonymous said...

THANK YOU!!! After trying to trouble shoot this one for over a week, your fix was the trick! I was just about to start pulling hardware...

For others who may be googling - allow me to put here the terms I've been searching on for a week:
- High CPU Usage
- High Hardware Interrupts
- System Idle Process 99% High CPU Usage

1/04/2007 10:15 PM  
Anonymous Anonymous said...

Well interestingly I was having the described issue, except my laptop's IDE controller did not indicate the mode was PIO. Regardless I uninstalled it and rebooted, hey presto.

My issue came after trying to backup my machine (software mirror) and the copying of a corrupt pst file. Fixing the pst with scanpst.exe fixed that, but my machine had already got itself mixed up so your fix has fixed the poor laptop. Thank you!

2/18/2007 10:47 PM  
Anonymous Anonymous said...

Thanks dude...been suffering with high CPU usage whenever installing or copying files. Your tip really helped! Thanks a million

2/21/2007 10:55 PM  
Anonymous Anonymous said...

Woohoo, thank you FrazzledDad! Thank you Google for finding this!

3/21/2007 3:25 PM  
Anonymous Anonymous said...

Thank you very much, was about to give up until I read your advice

3/28/2007 1:59 PM  
Anonymous Anonymous said...

I had this problem too with interrupts causing 100% processor usage. This fix did the trick.

Thanks a million.


4/02/2007 7:03 AM  
Blogger jonyboy said...

after third time un-installin windows coz of this problem.Now u really help me a lot thx dude ur Rock

4/23/2007 9:09 AM  
Blogger paul s said...

Thanks for the great find. I have been looking into this all afternoon.

I can't believe I had to add a reg key!

5/05/2007 7:57 PM  
Anonymous Anonymous said...

Yo thanks Daddio. My brosiff was all fandangled with this shiznit. Da laptop be screamin now.

6/18/2007 9:07 AM  
Blogger Jack said...

I have been attempting to track down my maxed out CPU because of hardware interrupts. I wanted to try focusing on the hardware but most everything I found on the Web was trying to fix processes. I desperately was looking for how to trap the interrupts to determine the offending device and I ran across your comments on DMA vs PIO --- BINGO. I knew when I read your piece that you were onto the exact same thing that troubled my system.
Worked like a charm and only required the uninstall and reboot cycle. As a side not my booting was 15 minutes until the fix.


6/23/2007 9:20 AM  
Anonymous Ochie said...

THank you very much sir! it really is the problem in my laptop. At first i thought it was a virus or a Spyware... i did all the scan..but to no avail..then i read your post XD..Wooooooooooot

6/26/2007 9:09 AM  
Anonymous Anonymous said...

just want to say thanks you saved the day I tried just about everything thought it was windows updates again but checked device manager and it was exactly as you had it all is well thanks again

7/10/2007 6:52 PM  
Anonymous Anonymous said...

yes i agree ... good info. thanks!

7/24/2007 6:50 PM  
Anonymous Anonymous said...

dude you are the man! BOOM SHAKALAKA!

8/13/2007 11:32 PM  
Blogger Brob said...

I'm not even able to begin to understand why this happened on my computer but I've been banging my head in frustration. I found your blog and was sceptical but gave it a go (not before backing everything up!).

It only flipping well worked. I can't believe it.

Cheers mate I owe you a drink.

8/19/2007 6:32 AM  
Blogger Adh3 said...

Thank you very much dude. I almost sold my Laptop just because of this problem. You fixed it!

9/29/2007 12:52 PM  
Blogger Vince & Siv said...

I've struggled for over a day thinking it might be USB issues, hard disk problems.....did what you said here and Shazam, PC back to normal! Like many people here, I owe you a pint!

10/03/2007 2:01 PM  
Blogger Miklatov said...

Fantastic advice! In the pas tI've always been sceptical about heeding advice offered online regarding computer problems, due to it never solving the problem I had.

This worked like a dream and saved me from sending my laptop back for a refund! I owe you a pint, mate!

10/17/2007 6:57 AM  
Anonymous NFrickelton said...

This worked, thanks a ton! I have no idea why it would shift over to that mode if it's so crippling. Why is it even an option?

10/21/2007 7:39 PM  
Blogger Jim Holmes said...

@NFrickleton: It's an option because older sytems needed that slow IO mode. It's crushing for new systems which should have the better mode, but not the older ones.

10/21/2007 10:14 PM  
Anonymous geoffvro said...

Thanks a bunch man, been trying to solve this for a few days now. Damn lucky that I came across this post, thanks again

10/25/2007 1:18 PM  
Anonymous farish said...

er... my IDE controller did not indicate the mode was PIO...
after i uninstalled and rebooted it, there's no change...
my pc cpu usage still high...
maybe there's any other ways to overcome it??

12/07/2007 2:04 PM  
Blogger Freshbru said...

Thank you soooo much! I thought my hard drive had died and was not lookinfg forward having to replace it.... Then I came across your post and everything was fixed in a matter of minutes! You are a legend my friend. All the best for the new year and have a prosperous 2008.

12/28/2007 11:02 PM  
Anonymous Albert Zablit said...

i no longer am suicidal because of my hardware interrupts. I owe you one ;)

thanks (you got no idea how much i mean that right now)


12/31/2007 2:30 AM  
Anonymous Albert Zablit said...

i no longer am suicidal because of my hardware interrupts. I owe you one ;)

thanks (you got no idea how much i mean that right now)


12/31/2007 2:34 AM  
Anonymous Anonymous said...

You are a true scholar my friend.
After sifting trough umpteen posts by supposed 'experts' chiding the unwashed masses that System Idle Process should be 99%, regardless of how high the memory usage is. I finally came across your information on how to resolve Hardware Interrupts, thoughtfully hidden within System Idle Process by Microsoft pinheads.
Aside : Process Explorer should entirely replace the Task Manager, which is completely misleading when dealing with these types of issues.

To sum up; You Rule!

1/06/2008 11:10 PM  
Anonymous Nikhil Wagholikar said...

Thank you very much FrazzledDad. Though I don't know what is PIO mode and what is DMA mode ... still my problem is solved. Thanks a million !!

1/07/2008 4:06 AM  
Anonymous Vince_vega said...

All I can say is - you are a LEGEND, mate! I have been having this problem for over a year now, regularly having to reinstall the system without finding the actual cause. And it turned out to be sooo simple! Pure genious! Stumbling this page is the least I can do for you. :)

1/11/2008 2:24 PM  
Anonymous Anonymous said...

marry me?


1/14/2008 12:02 PM  
Blogger Mike said...

Incredible - and in my case the IDE Controllers were set correctly to DMA, but out of frustration I uninstalled them and rebooted, and problem is gone.

1/16/2008 1:15 AM  
Anonymous Net Giant said...

Thank you! My machine had been having severe interrupt spikes for the last few weeks and I was beginning to think it was on it's last legs. Your research and blog post enabled me to locate the problem, fix it and keep this tired rig running. Thanks again.

2/07/2008 10:56 AM  
Anonymous Evan said...

This is an amazing find. I was stuck for weeks. I use my laptop in front of customers and when demonstrating our company's software I always blamed the slow performance on Windows. Nice to know that I was right.

2/08/2008 9:45 AM  
Anonymous Anonymous said...

Thanks very much. I thoght that it was a harddrive problem, I spent a lot of time googling what is the reason. Thanks man

2/10/2008 7:44 AM  
Anonymous Anonymous said...

I have been googling for 2 weeks with "high CPU & high system idle"...But your blog fixed the issue. I know a lot of people are having this issue but not able to fix it.


2/10/2008 9:39 AM  
Anonymous Anonymous said...

Simply put, THANK YOU! This saved me from insanity!!!! HUGE THANKS from Finland. I am now attaching this page to newsgroup (sorry, in Finnish) that discusses the same problem.

2/16/2008 4:43 PM  
Anonymous Anonymous said...

Almost 2 years later, and you're still helping others with this solution. THANK YOU for finding it. I've been looking all over for this fix. One IDE channel was in DMA mode, the other in PIO. Uninstalled them both, now they're both in Ultra DMA mode. YOU ROCK!!!

2/18/2008 7:59 AM  
Anonymous Anonymous said...

All those months of googling finally paid off! I am about to reformat my hard drive when I accidentally stumbled upon your blog. Thanks so much for this simple solution!

3/08/2008 10:24 AM  
Anonymous Anonymous said...

I add my extremely heartfelt thanks to the others already here. I know I would never have found this problem explanation and fix without your provding it. It eliminated considerable frustration on my part, and marital strife as well (from spousal frustration when it is deemed my role to keep the computer working well)!

Thanks very much.

3/09/2008 4:48 PM  
Blogger James said...

We had nearly written off our home computer after months of poor performance. Hours and hours of fruitless searching, reconfiguring, scanning, blah...! Thank you for your simple, elegant solution that worked right away!


3/09/2008 5:22 PM  
Anonymous Anonymous said...

I feel like crying. You solved it.

3/27/2008 1:13 AM  
Anonymous Anonymous said...

You are the Man

3/28/2008 9:09 PM  
Blogger noikeee said...

I'm in the same situation as most people here - I've been for 2 days trying to understand what exactly was going on here, and finally this fixed it. The computer is still a bit slow but much better, and at least it now seems to come from the actual applications I'm running. Thanks a lot!

3/30/2008 1:13 PM  
Anonymous Anonymous said...

wow, its 5 am and i been working on this for 9 hours straight.

that fixed the black screen after the windows splash screen for a minute and the crackly windows sound at logon as well as the momentary curser pause freeze and scroll bar lag.

and think about the logic behind it: nothing would fix it yet everything i tried was downstream from the IDE controller. i was tracing it up that way, i kept thinking it was a hard drive starting to fail but the hard drive is whisper quiet and passed all tets. the problem was downstream a little from where i was looking.

also the fact that i had tweaked every other facet of the machine with a vengence this fix reduced a bootvis boot time from 79 - 209 seconds down to 27 seconds.

4/05/2008 5:46 AM  
Anonymous Anonymous said...

amazing solution!! I had given up on me laptop due to this, have un-installed - re-installed windows about 4 times. Dell guys had given up and were talking about replacing the motherboard!! This works. I owe you a pint!

4/17/2008 2:56 AM  
Anonymous Anonymous said...

I had tried everything to sort this out. Only when I loaded Process Explorer and identified the problem that I found this. Resolved in less than 5 minutes.


4/17/2008 4:37 PM  
Blogger WattMan said...

The end of all my CPU troubles ... H/w interrupts had me going MAD!! I love my laptop again!!! Many thanks to you my friend :-D

4/19/2008 12:52 AM  
Anonymous Anonymous said...

Another commendation here.

My reinstalled winxp twice, then swapped the motherboard, then gave me a new laptop (using the old drive) First month no problems, then the slowness hit again. Found this and got out of PIO mode. Thank you for saving me from another 6 weeks of torture!

4/22/2008 5:00 PM  
Anonymous Michael Fritz said...

i was about to throw my laptop out of the window ... but you saved my life!!

5/03/2008 11:10 AM  
Anonymous rodrigo said...

Yep... more than 2 years after the original post, this still applies and still solving the nightmare situation... any ideas on what actually triggers it into PIO mode.

5/05/2008 11:14 AM  
Anonymous Anonymous said...

Fantastic!! I've been trying to ignore this problem for a month now, until I just couldn't take it anymore. Googled like everyone else, and thankfully clicked on your blog link.

Yep. My boot drive was in PIO. I think it's funny that I'm running XP sp3. This problem, as described in the MS KB, was supposedly resolved in sp1. Classic MS.

Thank you FrazzledDad, from another frazzled dad!

5/11/2008 1:04 AM  
Anonymous Anonymous said...

Excellent Advice !!. Was tearing my head up over what could have caused this !1. My only modification was to remove and reinsert the same hdd into my laptop. Since then things went to the dogs and all HDD tests came back fine. Checked the Controller only to find it In PIO mode and the cause of this grief !!

Thanks again.

5/14/2008 10:20 PM  
Blogger Aap said...

Thanks, this seemed to have helped solve my harddrive problems, especially after changing the registry so it wouldn't revert back to PIO mode because of 6 culmulative errors but has to have 6 consecutive errors instead now.

Anyway, thanks for taking the time to post this terrific solution :)

5/21/2008 10:52 AM  
Anonymous Vinnie said...

Hey mate, I don't know how thank ya.
I was about to throw tha laptop by tha window

5/26/2008 11:14 PM  
Anonymous Anonymous said...

Thanks for the fix, for whatever reason it took me a long time to find this post searching on Google.

5/28/2008 11:38 AM  
Anonymous Anonymous said...

Thanks for the Advice. But before I do this will I lose all of my data and have to re-install the OS?

6/14/2008 12:38 AM  
Anonymous Anonymous said...

Wow, I've been trying to figure what has been slowing down this laptop for days. Now it boots lickety-split.

Thanks a ton.

6/16/2008 9:50 AM  
Anonymous Anonymous said...

Thanks so much! You truly are a God among Men!!

7/05/2008 5:37 PM  
Anonymous Anonymous said...

Thank you very much mate, I was struggling to track-down the issue for about a week and your find/solution is just brilliant.
Thanks again !

7/14/2008 7:44 PM  
Anonymous Anonymous said...

My laptop thanks you. I've been dealing with this problem for months, but I was looking for an offending process.

Great work.

7/17/2008 1:30 PM  
Anonymous Anonymous said...

I cannot thank you enough for posting what was such a simple fix to such a debilitating issue.

15-20 minutes to get logged in and doing any work now down to 3 minutes. Hurrah!!!

7/25/2008 6:40 AM  
Anonymous Anonymous said...

Magic & so simple: was ready to trash the system with its 20 min boot, unending virus scan times, etc. Works like a dream now.

Wish I'd found your article weeks ago!

Many thanks

7/28/2008 5:55 AM  
Blogger Daniel said...

Such a simple solution to such an annoying problem. Thanks, now our 4-5 year old laptop is usable again!

7/29/2008 10:29 AM  
Anonymous Anonymous said...

Jim Holmes?? You may just as well be John Holms... 'cause you da' man! You put the thwack down on this problem.

I've been pissed about this problem for weeks now. Thanks for the fix.

8/06/2008 7:32 PM  
Anonymous Anonymous said...

THANK YOU! You have saved me from punching the next person who would ask me "Are you sure it's not spyware?"

8/11/2008 5:07 PM  
Anonymous Anonymous said...

You are a god! Thank you!

8/14/2008 1:15 AM  
Anonymous Anonymous said...

Truly excellent. I can't thank you enough for posting this. I was lost and now my machine is back to its proper behavior.

Best wishes to you and yours.

8/17/2008 2:19 AM  
Anonymous Anonymous said...

I was experiencing the same issue and uninstalling drivers fixed the problem. The IDE controller start using PIO mode after I removed the secondary hard drive on the system.

8/17/2008 1:07 PM  
Blogger Grey said...

I'm glad I came across this post.
I tried it and it worked like a charm.

8/29/2008 4:30 PM  
Anonymous Anonymous said...

Thank you very much, I've been looking for an answer for weeks.
Thanks from Madrid!!!

9/04/2008 7:51 AM  
Anonymous Anonymous said...


9/08/2008 8:41 AM  
Anonymous Randy said...

Like all the rest, after using process explorer to find the interrupt issue, your post was the exact fix I needed. I also appreciated you giving the step by step on where the fix was. Too many times it is assumed that everyone knows what you mean. You are a great teacher.

9/16/2008 10:41 PM  
Anonymous Anonymous said...

Beautful! Worked like a charm. My kids are pissed off though - they almost had me going out to buy a new computer.

10/06/2008 3:11 PM  
Anonymous Scott said...

haha, this worked for me after a 48 hour witch hunt for everything from smoothscrolling disabling, virus scan, updates....shlwapl.dll worries! Recently i'd added an external hard drive that upon boot apparently scrambled by IDE setup. This was the problem the whole time, thanks! I did not even back up my system before running uninstall on both controllers.

10/07/2008 2:25 PM  
Anonymous Anonymous said...

this solved my problem after suffering a week of lousy performance issues caused mainly by hardware interrupts high cpu usage.

im using Dell D600 laptop and it feels like it's in core2 quad processor now...

10/18/2008 1:27 AM  
Anonymous Anonymous said...


10/18/2008 4:38 AM  
Anonymous Anonymous said...


I can't believe I ran across this post..I've been searching for an answer to this problem for weeks!

Static sounds
Mouse freezing
Slow cpu
high interupts
slow to copy or burn files

I have no idea why this happened in the first place

10/28/2008 7:36 AM  
Anonymous Anonymous said...

Kudos to your post. Never had had a problem with the NC8230 I use for work. Then I screwed up and put in XP sp3 and Office 2K7. Things really slowed down. Not sure exactly when IDE transfer mode reverted to PIO. I have lived with molasses speed processing for at least a couple of weeks. Found your post finally and voila, things are running fast again.


11/01/2008 5:19 PM  
Anonymous Anonymous said...

THANK YOU VERY MUCH! this soleved also my problem of hardware interrupts.

11/11/2008 10:59 AM  
Anonymous Anonymous said...

WOW! Thank you SO MUCH for this. I"ve been looking for a solution to this for a LONG time...and I finally found one! Who knew it was such a simple solution?
Thanks again!

11/18/2008 3:38 AM  
Anonymous Anonymous said...

FrazzledDad... you are THE MAN! I've been having this problem for a couple of weeks now & I was just resigned to thinking that my computer was dying, but this fix did the trick.

Thank you SO MUCH!

11/23/2008 7:48 PM  
Anonymous laptop Specialist said...

it solved my problem. just have to say thank you.

11/25/2008 5:05 AM  
Anonymous Anonymous said...

I Have reinstalled XP twice already because of this problem. Thank you so much for somehow finding the fix. You saved me from reinstall number 3.

11/25/2008 3:34 PM  
Anonymous Anonymous said...

Thank you, thank you, thank you! All other web sites (from Experts Exchange to Sysinternals forums) failed to provide a solution. Hurrah to the people that voluntarily post the solutions to their problems. FrazzledDad, you are going to the hall of fame.

11/27/2008 3:58 AM  
Blogger RodeoFive said...

Thank You Sir!!!

I had this problem for months and finally came upon your solution! I'm so happy now you wouldn't believe it!

12/03/2008 8:52 AM  
Anonymous Anonymous said...

Thanks very much FrazzledDad, this mystery is finally unveiled!

12/05/2008 2:01 AM  
Anonymous Anonymous said...

I think Monkeys are funny!

p.s. Thanks for the fix!

12/06/2008 8:10 PM  
Anonymous Anonymous said...

This did the trick for me too.... Many thanks. (Don't know how you figured this out but congratulations anyhow.)

12/15/2008 9:05 AM  
Anonymous Aaron said...

I too, like a thousand others apparently, have been searching for ages. I reinstalled my pc once, was happy with it. Suddenly, the problem came back. I did not want to reinstall...

And now, "it just works". You are a hero!

These were my common search term was:

Hardware Interrupts 100% CPU
Disk IO takes 100% CPU

I'm so happy!

12/21/2008 4:02 PM  
Blogger albee said...

hey his appears to be my problem and fixes i fine but it reset he last 2 nights i went to sleep. any ideas?

12/28/2008 3:01 PM  
Blogger albee said...

oh nevermind i've reread the post : )

12/28/2008 3:06 PM  
Blogger albee said...

hmm i tried downloading the hotfix from microsoft but i'm in sp3 and it won't install because it is for older versions.

12/28/2008 3:19 PM  
Anonymous Anonymous said...

I just have to sat Thank YOU! Close to three years later and this post is still helping.


Mitch in NYC

1/02/2009 7:45 AM  
Blogger leon187 said...

Thank you, it helped me a lot.

1/19/2009 11:34 AM  
Blogger Pascal said...

This is very useful. I was looking for this matter since a while.
As said all other many thanks.
Merci. Pascal

1/22/2009 3:04 AM  
Anonymous Ehsan said...

Thanks, I was really hopeless.

1/28/2009 1:50 PM  
Anonymous Anonymous said...

Found your post immediately after googling for 'hardware interrupts' and your solution worked like a charm - though it needed two attempts. Still don't know why my pc changed to PIO mode, but did spot a number of write timeouts on the event log a couple of days ago.

Nice to know after several years your post is still valuable!

2/04/2009 8:03 AM  
Anonymous Anonymous said...

Duuuuuuuuude, I LOVE YOU!!!!
Spent the best part of the last two days looking for a solution! You rule!

2/05/2009 3:58 AM  
Anonymous Anonymous said...

Many Thank...I no longer feel like I am swimming in molasses when I use my laptop.

2/11/2009 2:40 PM  
Anonymous Anonymous said...

G Damn it bro, you are the shit...

2/13/2009 1:32 AM  
Anonymous Anonymous said...

FrazzledDad you totally ROCK!!! I've been fighting this problems for weeks. Despite the fact that the evil empire claimed to have fixed this with XP SP2, it is still occurring. You nailed it and it's like I have a new machine again.


2/13/2009 8:15 AM  
Anonymous Anonymous said...

Thank you, sir. No viruses, no spywares, just old random-computer-error as usual ;)

2/15/2009 1:06 PM  
Blogger Todd said...

Thanks so much!! We tried 3 times last year and now.... magic! saved my daughter a bundle on geeksquad.

2/19/2009 9:43 AM  
Anonymous Anonymous said...

Bless you wise one!
Thanks for sharing this!!!!!!!!!

3/01/2009 9:52 PM  
Anonymous Anonymous said...

Hey do you know how can we do this trick on vista too? Ty!

3/15/2009 2:49 PM  
Anonymous Anonymous said...

A great THANK YOU from Italy too! This fix solved my problem! GRAZIE! Stefano.

3/16/2009 1:33 PM  
Anonymous Anonymous said...

Thank you sir, you are a god amongst men

3/16/2009 4:05 PM  
Anonymous Richard said...

Hey Jim using your info here I have just fixed a laptop that was taking ages to get to the desktop in normal mode. You were spot on with your advice. Primary was set to PIO mode. After deleting the driver and rebooting it went to Ultra DMA mode 5. Its running great now!!! Many thanks from Richard at

3/21/2009 4:06 PM  
Anonymous Anonymous said...

This fixed the mysterious problem on my family's computer. It seriously had trouble loading Youtube videos without skipping! Going from PIO to UDMA5 made all the difference. All manners of tune-ups failed before this.

Thank you!!!

3/23/2009 3:37 AM  
Blogger HarryC said...

I've been struggling with a acer laptop that belongs to a friend. It suddenly started booting very slow and over all had bad performance. This simple solution fixed the problem. Thanks for posting your findings! I'll be able to give him back his laptop w/o doing a wipe and reinstall!

3/24/2009 7:59 PM  
Anonymous Anonymous said...

Just in case someone else with the same problem comes here via Google:

This issue is not always caused by hard drives set to the PIO mode. In my case, the reason for about 30% interrupt-caused cpu usage was a Vista 64 driver for a Marvell 61xx RAID controller, which can be found on Asus P5Q mainboards. If you don't need a RAID, simply disable the device in Device Manager and cpu usage should drop to below 2%. As of 03/30/09, there is no driver or BIOS update available at Asus which could fix the problem without having to disable the RAID controller.

Note: If you don't install the RAID driver at all, your PC won't shut down correctly, so it is advisable to install, then disable it.

3/29/2009 8:01 PM  
Blogger Ed said...


I would just like to say you saved me a lot of painful, hard work. I read your blog about hardware interrupts and the solution being to uninstall my primary IDE channel and let windows fix it. I have been ripping my hair out and searching for solutions everywhere, only to find that your simple and quick solution works. Thank you so much and keep up your blogging you're doing great work!

3/30/2009 7:14 AM  
Anonymous Anonymous said...

Massive thanks, my PC just started having this problem (only after it had been running for an hour though) and I was at a total loss as to what was causing it.
All other sites I found on the problem did not help, but uninstalling the Primary IDE driver that had reverted has fixed the problem completely. Can actually use my PC for more than an hour at a time again now :)

4/02/2009 5:55 AM  
Anonymous Anonymous said...

You Rule........
I was about to spend a fortune to get a new computer after getting fedup. You saved a lot frustration for me...

4/08/2009 2:31 AM  
Anonymous Tyler said...

You have no idea just how much better you just made my life.

I completely reinstalled my machine because I couldn't get rid of the high CPU usage, then it was still there after reinstall... UGH!!

Your solution worked.

I wonder how many hours I've wasted reinstalling friends computers when the fix may have been as simple as this.

4/16/2009 8:54 PM  
Anonymous Anonymous said...


4/20/2009 6:29 AM  
Blogger acastellanophoto said...

I don't know if you even check this page anymore, but I just have to hope you do and add my thanks along with all of these grateful people. This problem has plagued my computer for over a year making running any multimedia - video or audio of any type pretty much unbearable. I have tried forever to diagnose this problem, visited a lot of tech sites, loaded a ton of different optimization programs - all to no avail. Until now. You have given my machine back to me, and the fix was so ridiculously simple. Thank you very much.

4/24/2009 11:59 PM  
Anonymous Muñequito Antiestres said...

Your my personal Jesus, thanks.

4/27/2009 7:22 AM  
Blogger MzKoRE said...

OMG! my system was faster than before at first it tooks 5 min to startup, now only 2 mins! THANKS A MILLION!!!

5/09/2009 1:41 PM  
Anonymous Anonymous said...

This fix saved me the trouble of reinstalling Windows. Thanks so much for the fix and please get this out to more people!

5/13/2009 9:07 PM  
Anonymous Anonymous said...

Truly excellent information!
Why isn't this Google's number one?

Thank you!

5/22/2009 8:48 PM  
Anonymous Neo said...

Give this man a statue.
I work at HP and 5 guys from our own helpdesk just stated to me to re-image my disk.

What a bunch of ....

Thank you again

5/24/2009 3:23 PM  
Blogger Rincey said...

I too think you deserve a beer....

too many other links were full of BS... yours was simple

5/29/2009 7:30 PM  
Anonymous Anonymous said...

Worked like a charm. You are a wonderful human being. Thank you.

6/04/2009 11:58 PM  
Anonymous Anonymous said...

Thank you!!! You saved my life (and my marriage) You ROCK!!! That it would be so simple...

6/07/2009 9:11 AM  
Blogger Chris said...

Thanks a bunch!! Comp works so much better now!!

6/11/2009 5:26 PM  
Blogger Jessica said...

Thanks soooo much! I have been dealing with my super duper slow computer for months now. I thought I would have to replace it. It was such an easy fix, after I could find my device manager

6/12/2009 1:22 PM  
Anonymous Anonymous said...

after using process explorer i alos had a high usage of the hardware interupts problem. basically it was totally consumming 1 of my cpu's. after checking the ide transfer staus mine was not set to PIO but i'd thought i'd try you fix all the same.

uninstalled the driver, reboot.....all was well

thx man! :D

6/20/2009 9:45 AM  
Anonymous Anonymous said...

You Still Da Man! 6/25/09

Saved me days I am sure!


6/26/2009 12:34 AM  
Blogger Surya said...

this thing just worked like charmed.
just bang on!

6/29/2009 3:09 AM  
Anonymous Brooke said...

WOW!!! thank you so very very much, I have been trying to fix all these different things on my computer for over 2 weeks because it has been so sssslllllloooooowwwww..... I was looking at process explorer and saw the hardware interrupts using 99%! I have been googling all over looking for help and this did it thanks so much!!!!

6/29/2009 5:56 PM  
Blogger Ray said...

Your solution worked like a charm. Thanks!

7/12/2009 7:05 PM  
Blogger Chrys Alex said...


7/14/2009 9:52 PM  
Anonymous Anonymous said...

THANK YOU!!! you fix my problem

greeting from Chile!!

7/25/2009 11:39 AM  
Anonymous Steele said...

My system was working just fine until I installed a SATA drive as a data drive. Talk about interrupt problems... lets put it this way, >80% CPU usage nearly 80% of the time. All drivers were updated, and I did a clean install of XP before installing the SATA.

Unfortunately, this did not work for me. Upon the second reboot, checking with Device Manager the Primary still stated it was still PIO. And the secondary is on DMA.

So back to the drawing board of why my Primary stays on PIO.

7/26/2009 8:42 PM  
Anonymous Anonymous said...

this totally worked for me

thanks a million!!

8/11/2009 3:06 PM  
Anonymous James M. Young said...

I can't thank you enough for this tip, I'd been pulling my hair out for days, running every sort of spyware and virusscan under the sun! You're explanation explains why the system was dog-slow even in safe mode or with diagnostic boot-up. Thanks so much!!

8/17/2009 12:11 PM  
Anonymous Anonymous said...

AWESOME!!!!! Did the trick. Thanks a million!

8/21/2009 12:47 AM  
Anonymous Anonymous said...

I have an Acer Timeline Laptop (3810T) running on Vista Home Premium experiencing the same sluggish operation. I didn't find the Advanced tab as described but uninstalled the driver just the same. It worked like charm and mu laptop is running good. Thanks for this info!

8/25/2009 10:26 AM  
Anonymous Anonymous said...

Amazing that Microsoft hasn't fixed this yet. It just worked for me on XP x64.

8/27/2009 1:29 PM  
Anonymous Laptop Repair Service said...

Amazing piece of information...actually I was looking for this kind of stuff for my laptop.

9/09/2009 9:18 PM  
Anonymous Anonymous said...

Thank you!!!

9/17/2009 11:42 AM  
Anonymous Green_Cabbage said...

I had the same symptoms, and FrazzledDad's great solution didn't apply to me. I found a different solution to the same problem.

Go to "Device Manager" >> "System Devices" >> and disable "Microsoft UAA Bus Driver for High Definition Audio"

My issue is now fixed.

good luck.

9/19/2009 10:43 PM  
Blogger shiv said...

Unbelievable. thanks a ton. I too was suffering from high cpu usage and my laptop had simply become a crippled entity. The solution is so simple was totally unbelievable. My laptop is now leaping like a leopord. I am extremely obliged to the person for posting the solution. Many many thanks once again to the person, to the blogsite and to the phenomenon called INTERNET which made it possible.

9/24/2009 1:21 AM  
Anonymous Larry the Computer Guy said...

I am so glad you published your interrupt fix. I had a customer laptop that sysinternals showed extreme high CPU usage, but it didn't show why. Thanks from me and the hundreds of others that you helped.

9/27/2009 10:16 AM  
Anonymous Perry said...

You are the baddest, after a month of thinking my older laptop was dead, and the wife almost had me convinced to go buy her one of those new little netbooks, you saved me 300 bucks!!

I owe you a beer!

10/01/2009 11:30 AM  
Anonymous Anonymous said...

Thank you so much for the solution. This not only reduces the CPU usage to a very low percentage but also solves my hibernation problem: it used to take about two minutes and now it's down to 25 seconds! I searched everywhere for the long hibernation problem solutions but no one else had a clue.

10/01/2009 5:56 PM  
Anonymous Anonymous said...


I've have been trying for months to figure out why my desktop PC was so stinking slow. I could only put up with the problem buy using my laptop instead.

I though I might have a virus or spyware. I blamed Windows Security Updates (and removed them). I shut down Counter Spy because I thought it might be in conflict with Kaspersky.

When I looked at my IDE ATA/ATAPI controllers they still said "DMA if available" and not PIO. I went ahead and deleted them anyway and rebooted.

XP automatically restored them and the problem went away.

I can't tell you how happy I am to have my PC back.

10/04/2009 4:20 PM  
Blogger Vladimir said...

Thank you!

10/06/2009 11:03 AM  
Anonymous Anonymous said...

This also solved my problem, thank you so much!

10/06/2009 9:21 PM  
Anonymous Anonymous said...

Thank you sooo much! I've spent literraly months trying to find a fix for this problem..! But, do you happen to know what causes the problem at the first place? I mean, according to MS, DMA turns to PIO after many CRC's have occured, but, what might be the cause of these CRCs? (given i have the latest Service Updates installed of course)

10/07/2009 4:27 AM  
Anonymous Anonymous said...

Thank you so much. solved the problem immediately.

10/09/2009 6:28 AM  
Blogger Will said...

Jim, I cannot thank you enough! I was afraid my PC was about to kick the can, but your fix worked like magic. I, like many other people it seems, owe you a pint! Thanks again.

10/09/2009 6:25 PM  
Anonymous Anonymous said...

The PIO mode solution... this is parfurm water.
All W SO are afflict to performance i/o issue. I'm working on this in my firm from 3 days w/o solution.
The fltmgr.sys is the wall and fltmc command is not useful for diagnose the problem.
The PC are not ghosted, are formatted from W CD.
The i/o performance issue not depend from SP / Windows Update installed.
The PC HW and SW are all different.

10/17/2009 1:56 AM  
Blogger rpr said...

[quote]Turns out ATA/IDE controllers will often revert back to PIO mode instead of Ultra-DMA. (MS KBA 817472)[/quote]

Jim, thanks a lot for this hint. It solved the problem here on a MS Win XP SP3.

BTW, I looked at MS KBA 817472 which says: "This problem was first corrected in Microsoft Windows XP Service Pack 2."

As my problem occurred on a XP SP3, it seems the problem is not fixed well enough in SP2 or they revoked the fix in SP3.

-- rpr.

10/19/2009 6:42 PM  
Blogger Sachin said...

Thanks for the solution. Got rid of tortoise-paced computing.

10/21/2009 4:02 PM  
Anonymous Anonymous said...


10/22/2009 1:40 PM  
Anonymous Anonymous said...

I saw very high (50-70%) usage for "Hardware Interrupts" in Sysinternals Process Explorer. Your blog post has cured it. It was in fact currently using "PIO" and is now "Ultra DMA Mode 5". Brilliant dude!

11/01/2009 10:17 AM  
Blogger JacobG said...

I can now die happy. Cheers.

11/02/2009 5:24 PM  
Anonymous Anonymous said...

You are a legend - thanks a million !

I have been suffering with my pc running slowly for weeks and this helped me to solve it in 2 minutes flat !

11/07/2009 6:14 PM  
Anonymous Radu said...

MANY THANKS! I was searching the problem for one week and you saved me.

11/14/2009 1:25 AM  
Anonymous Bjarne Dahlin said...

Thank you very much!

Turns out I had forgotten about a CF card in my laptop, and it was causing some 50% CPU usage that only ProcessExplorer could reveal. Windows Task Manager didn't have a clue.

Will look into the PIO issue as well for the main HD - in case it happens again.

11/30/2009 1:46 AM  
Anonymous Anonymous said...

London 2009 - got this problem, found your blog and am really appreciative that you took the time to post this and help so many people. My machine is up to speed again thanks to you.

12/05/2009 7:05 AM  
Anonymous Anonymous said...

oh my good luck..i m fortunate to find this..After implementing the fix i got my system back..what a brilliance..i am really appreciating it..Thanks a lot..

12/06/2009 2:21 PM  
Anonymous Anonymous said...

This was a VERY SIMPLE fix! Thank you so much. My mother's laptop has been like this for almost a year. I thought it was a faulty hard drive. I still have some other issues but my system isn't crawling anymore.

12/15/2009 1:36 PM  
Anonymous Anil said...

great advice. Thanks.

12/16/2009 4:18 AM  
Anonymous Ted said...

What can I say. This is brilliant. Speeded up my Dell D620 by at least 10X. THANK YOU! This goes in my toolbag.

12/18/2009 6:09 AM  
Blogger Benjie said...

Thanks man... It helped me a lot... Your a life saver. Hope many would still find this solution as it really works

12/20/2009 5:07 AM  
Anonymous Anonymous said...

It's a good job someone understands these dohickeys.
Thanks a lot.

12/22/2009 3:07 PM  
Blogger Dan said...

well i did what this article says but unfortunately it did not work my hardware interrupts jump around the 62% marker and even uninstalled a system device from old hardware which worked till i rebooted again. I guess i'm outa luck.

ANy HELp OUt therE????

12/23/2009 8:53 PM  
Blogger DigitalDog said...

3 years later and this post is still helping people - I just not only improved a sluggish system, but boosted my data transfer rate from my DVD drive by about 4x - 5x. Thanks!

12/26/2009 2:03 PM  
Blogger Jeff England said...

I have to agree with a previous comment. It is amazing that after 3 years, this single entry still helps so much. My sister in-law sold me this computer for rock bottom price because it "didn't perform" as she would expect. I used ProcExp and saw the problem right away (interrupts). This was the second article I read on this issue, tried the fix out, and instantly saw the improvement. I, myself feel like a frazzled dad often while trying to keep the 5 laptops in our household in working order.
Keep up the excellent help, and Thank-you.


12/26/2009 4:55 PM  
Blogger goblinbox said...

This post just solved the recent and frustratingly inexplicable hardware interrupts on my netbook. I was just about to do a full opsys reinstall; you totally saved me, like, a whole day!

12/28/2009 2:23 AM  
Anonymous Anonymous said...

Thanks dude =)

1/08/2010 8:29 PM  
Anonymous Anonymous said...

Thank you.

1/11/2010 6:44 AM  
Blogger SpaikY said...

Thanx alot man but here is the problem that this problem is happening with me but at windows 7 and i can't solve it cause there is no "Current Transfer Mode field " in the device manager so ...

i hope u can tell me the solution i really hope so cause it's very annoying

1/19/2010 10:03 AM  
Blogger Diogo said...

I can't thank you enough! Solid gold!!!

I was thinking on buying a new laptop! This blog post saved me a thousand USD!!

Thank you! Thank you! Thank you!

Oh... and thank you!

1/21/2010 6:52 PM  
Anonymous Mike J (NZ) said...

I was almost driven mad, I found an issue with the HDD in my laptop, so I replaced this, and did a GHOST image from ol to new drive, and my syste progressively got slower (again no viruses/adware/spyware located). I installed process explorer to find our the Interrupts running at >85%, after about a month or so or driver by driver re-installs, and windows repairs I came across your post, and I can't believe how simple this was, you are a legend, and now on my list of heroes, thanks, and EVERY engineer needs this in their bag of tricks.

1/22/2010 3:54 AM  
Anonymous Anonymous said...

Let it be said that I know next to nothing about computers. I'm the type of guy that walks into Best Buy and all the little twerps behind the Geek Squad counter see a walking ATM.

So when I subscribed to Carbonite's 15-day free trial a couple of weeks ago and found that soon after my computer slowed to a crawl I knew I was toast. Luckily the IT guy at work loaded something called Process Explorer on my system. I noticed immediately that "Hardware Interrupts" was averaging a constant 75-85% CPU usage. I googled the term, found this page, followed your instructions, and BAM! Works like new! FrazzleDad... you rock!

1/29/2010 9:11 PM  
Blogger guillermoramirez said...

I detected the problem of 100% cpu usage with acer aspire 5000,

2/06/2010 9:09 AM  
Anonymous Anonymous said...

Thank you very much, man! That's solved my problem!!!

2/08/2010 1:03 PM  
Anonymous Anonymous said...

Have no idea what PIO or DMA are, but this fixed my problem! Thank you!

2/13/2010 12:36 PM  
Blogger Claudiu-Cristian said...

Dude, you probably just saved me days of torment - I just started having this problem today and I was lucky enough to run into this page after only a few minutes of googling. Obviously, your fix solved my problem instantly and now everything works perfectly!
Thank you man, really! You totally rule!

4/11/2010 1:51 PM  
Blogger Immortal_Jas said...

Thanks a lot man.......and now I can buy myself a guitar.......i thought i had to buy a new laptop until i found the solution u gave me here! awesome damn awesome........:)

4/18/2010 10:44 AM  
Anonymous Anonymous said...

Great stuff mate. Been doing my head in for ages, now it's sorted! Saved me a format/re-install and lots of wasted time.

4/22/2010 11:52 AM  
Anonymous Joshua said...

Holy $h!t am I glad you posted this (I am just under four years behind the curve.)

Process Explorer and "Hardware Interrupts," spent the last month trying to convince my wife I had not downloaded SARS and Bird Flu.

Thank you !!!!

5/12/2010 3:32 PM  
Anonymous rpr said...

MS Windows XP strikes back with PIO transfer mode! I had to fix it again (the first time was 7 months ago -- see above). Really a PITA.

The problem came back after installation of a USB 3G modem (Huawei E1552) which added new virtual COM ports and two drives (a virtual CD-ROM and a microSD memory card).

-- rpr.

5/16/2010 5:48 PM  
Anonymous Anonymous said...

After struggling for two complete days, I could resolve issue of my slow PC thanks to your blog...

5/25/2010 7:07 AM  
Anonymous phoenix studio™ said...

i love you man..

6/15/2010 12:10 PM  
Anonymous Keith-Watford-UK said...

Jim, Here we are June 2010 and your advice has fixed a long running problem. Thanks to you and hippocritically Bing for your help.
Shame on you Microsoft :-)
Another Hey Presto!! Thanks.

6/26/2010 5:27 AM  
Blogger nigelsiederer said...

Thanks so much. I've put up with this problem for 3 years: slow running, 15-20 minutes to boot up. And it got worse. The laptop seemed reluctant to multi-task. When the mouse started to refuse to accept taps without a delay and the keyboard was getting slow, I had to find the answer. I initially blamed Norton 360, whose Live Updates took an age and consumed CPU resources. But an upgrade to Version 4 much improved that problem. There was a hitch with the upgrade, so I phoned Symantec's reputedly unhelpful and expensive helpine. In fact they were quite good (and didn't charge), but remarked on the slow performance of my PC - Norton, with their reputation for not caring about how their products slow computers down, thought my computer was too slow! Time to look further. Process Explorer was still showing Hardward Interrupts as consuming CPU resources. Sure enough, the setting on the IDE controller was wrong, so with heart in mouth I uninstalled it, and on reboot, it reinstalled with the problem corrected. I then ran the Hotfix from Microsoft and carefully followed their register edit instructions. Problem solved. The boot now takes about 3 minutes. It multi-tasks properly. the mouse clicks. In short, it's once again doing what a laptop should, and I'm no longer tempted to throw it out the window in frustration. Thanks again for posting this solution.

7/08/2010 11:55 AM  
Anonymous Anonymous said...

I thank you very much for the post and for all the comments that googled me here. Had a sudden degradation in performance. One CPU was maxed out, had scratchy audio playback and the mouse was jerky. Your fix took minutes and now (after I turned off most of my Services) my Dell D820 absolutely screams. Thanks again.

7/09/2010 8:26 AM  
Anonymous Anonymous said...

Can't say much of what hasn't already been said. Thanks from another Dad who was about to openly weep in front of his children. This machine runs great now.

7/10/2010 1:29 PM  
Anonymous Anonymous said...

Acer Travelmate laptop running Windows XP - had the same problem - even moving mouse caused increased cpu usage due to hardware interrupts. Tried resetting the primary and secondary IDE controllers - no change. Then read about restoring the defaults on the VGA display graphics controller. Go into Control Panel>Display then select Settings tab in Display Properties window then Restore Defaults button. Then Apply button. Laptop now lightening fast, multi tasking and no fan noise turning on and off constantly. Mightly relieved and such a simple fix although no idea how or why the problem arose.

7/12/2010 8:02 PM  
Blogger Mal said...

Fantastic! thanks.

8/10/2010 7:43 PM  
Anonymous Anonymous said...

Ok... Simple, explained, easy to follow instructions that actually fixed my computer issue? Is the sky falling? Thank you! I've been going in circles with this same problem for a while now and I can't believe this worked.

8/14/2010 8:19 AM  
Anonymous Anonymous said...

just WOW
this trick magically sorted out all my problems
thx man

8/21/2010 9:45 AM  
Anonymous Laptop Repair said...

Great comments all around! I like how there are a variety voices coming through.......

8/24/2010 7:54 AM  
Anonymous Anonymous said...

Thank you, 1000 times.

8/27/2010 9:00 PM  
Anonymous Anonymous said...

Wow. Thanks a lot man :) Helped me solve an issue outstanding for days that my IT support couldn't fix.

9/02/2010 3:10 PM  

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