Troubleshooting : High CPU usage for hardware interrupts

Author: shubhamjain
Subject: High CPU usage for hardware interrupts
Posted: 03 August 2013 at 10:10am

Image may be NSFW. Clik here to view. DetroitDave wrote: Finally!  I found your site and this (totally simple) solution to my hardware interrupt problem!  XP had indeed reset my IDE/ATA controller settings from DMA to PIO.  Removing the driver and restarting the pc fixed it.  Meanwhile,  I had spent a week looking around for a solution to my pc slowdown problems (Toshiba Satellite laptop with a Hitachi hdd) until I almost accidentally ran across this thread on your excellent forum.  Apparently this issue -- Windows resetting DMA transfer to PIO -- is fairly common (see: http://support.microsoft.com/default.aspx?scid=kb;en-us;817472, for instance) -- yet it's not the among the common solutions that show up when searching the internet tubes for "system slowdown" (or the like) issues.  I don't know how many wild goose chases I followed -- (virus?, hard drive or other hardware issues? malware?  etc., etc.) before discovering the simple solution discussed here.  Many, many hours wasted.  Sigh. Which reminds me to ask:  If Windows, based on things like a few bad restarts in a row, more or less routinely resets the drive controller to use PIO instead of DMA, then why does it not give a large WARNING about what it's doing, why it's doing it, and mention that it will severely hamper system performance and maybe also mention, by the way, how to reverse the setting(s)? Maddening!! Finally, though I am not a total noob, casual suggestions to "delete drivers and let XP fix them on reinstall" can seem a bit disconcerting to the ordinary user.  At the risk of redundancy (and boring the geekier reader to death) here, for the ungeek, is the full step by step way to check to see if XP has turned off your DMA mode and how to get it back if that's the case. This assumes a mostly vanilla setup with a standard IDE/ATA drive controller which is probably the case for most pc's that have this particular malady. Right click "My Computer."  Choose "Properties."  Select the "Hardware" tab. Select the "Device Manager" button. Expand (click the + sign) next to "IDE ATA.ATAPI controllers" Right click "Primary IDE Channel" Select "Properties" Select "Advanced Settings" ... here you will now see the ATA/IDE devices for your system.  Typically you are concerned about your system hard drive which is called "Device 0" (zero).  There are three boxes under Device 0: Box 1: Ensure that "Device Type" is set to Auto Detection Box 2: "Transfer Mode" should be set to "DMA if available" Box 3:  should read "Ultra DMA Mode 5" (or something similar) If that is how it all reads, this is not your problem.  But iff Box 3 reads "PIO" then XP has indeed reset your transfer mode to the slowest setting which will cause up to 100% kernel processing time for long periods of time to accomplish even simple operations..  So now you know what your main problem is!  To fix this don't go anywhere! Stay in the same Device Manager "IDE Channel Property Settings" dialogue box. Select the "Driver" tab at the top of the dialogue box (next to "Advanced Settings"). Select "Uninstall"  (the very bottom button). Say OK and allow the system to reboot.  I know, it seems counterintuitive and maybe a little scary to just uninstall this thing... how will the system know what to use when you restart it?  This you have to take on faith.  Why doesn't Microsoft explain here what XP is about to do?  I dunno.  But hold your breath and do it anyway.  When you reboot your pc, Windows XP will notice you don't have this driver installed, and it will select one for you automatically.  It won't even ask and it won't even tell you until your desktop loads and there, you should see one of those goofy little bubbles in your system tray that says something like "XP discovered new hardware (your diskname here) and installed it for you." "What!??" you say?  "I didn't install any new hard disk!"  Heh.  I know, but that's what XP says when it finds and re-installs the driver you removed. You should also notice that your pc suddenly works a lot faster and that Process Explorer (or even the simplistic windows taskmanager.exe) is not showing gigantic amounts of CPU kernel time being dedicated to reading hardware interrupts.  Now if you go back through the above steps, Device Manager may show that "nothing" is selected in Box three, where you'd expect it to see "Ultra DMA Mode 5" or the like.  This will show up when you reboot again and, barring other problems, all will be right with your world again. Thanks for this great forum and for excellent tools like Process Explorer!

DetroitDave, thank you loads! I have been having this problems of a slow computer from a long time & it had got on my nerves. The symptoms of this problem were:

slow booting of windows
slow speed of file transferring
slow opening of any file
hd video files hanging while playing

There was a rise in hardware interrupts during these symptoms (known to me thanks to process explorer). I searched a lot for the solution. Reinstalled Windows to no avail. Uninstalled graphics & audio drivers but no improvement. This was until I reached this forum & executed DetroitDave's in detail procedure which worked like a charm! Thanks a lot!