DPC (Deferred Procedure Calls)

Could you please confirm whether the DPCs are also present when the system is idle?
Please make sure that both dbghelp.dll and symsrv.dll from the Debugging Tools for Windows are present in the same directory as Kernrate_i386_XP.exe.
Then try the following command while online:
Kernrate_i386_XP.exe -m -b 4 -i 2500 -w 3 -s 10 -k 3 -j "symsrv*symsrv.dll**http://msdl.microsoft.com/download/symbols" -z hal -z intelppm -z ACPI -z ntkrnlpa >output.txt
and please upload the output.txt file here.

Hi Haysys,

The file you uploaded is not a kernrate output file (it's used for symbol resolution).
Please try first to launch kernrate without symbols options while the system is idle (no applications running)
Kernrate_i386_XP.exe  -w 3 -s 10 >modules.txt
and upload or copy here the resulting modules.txt file; so that we can first check what are the modules used the most.

I had the same problem and have resolved it.  On Lenovo W500 I noticed a steady 17% CPU on one  core.  I installed Process Explorer and saw that it was all due to DPCs.  I used kernrate to determine that it was my Conexant SmartAudio HD driver - CHDAU32 - when Process Explorer showed this condition (frequently, for a couple of minutes at a time) I fired up kernrate for about 30 seconds or so, then hit control C to view the kernrate results.  I checked the driver version against Lenovo's website and it was at current level, but I decided to download the current driver and install it again.  The problem has not reappeared.  Kernrate identified the problem child, but kernrate is not too user friendly.  Try this:
- download kernrate  http://www.microsoft.com/downloads/details.aspx?familyid=d6e95259-8d9d-4c22-89c4-fad382eddcd1&displaylang=en
- run it and perform the setup in the KrView folder
- open a DOS window and cd to the program files\KrView\Kernrates directory
When you notice your problem child running hot in Process Explorer...
- fire off the kernrate_i386_XP.exe command (no args needed)
- let it run for 30 seconds or so and then press control c
You will see the output in the window.  My list shows CHDAU32 ranked as number two in CPU time the smoking gun...
Time   22611 hits, 25000 events per hit --------
 Module                                Hits   msec  %Total  Events/Sec
ntoskrnl                              19582      28859    86 %    16963512
CHDAU32                                2128      28859     9 %     1843445
hal                                     623      28859     2 %      539692
win32k                                   72      28859     0 %       62372

Good luck with your drivers...

Are you saying that you solved your performance issues by enabling Driver Verifier? That is entirely bizarre, I'd guess that something else changed as well since Verifier makes thing slower by definition.

Thanks Phil, but i tried plugging the adapter into 2 different slots with no luck ( although booting with with it unplugged certainly worked well :-)  ).  If  you are taking about port as in something that can be changed through software then I have no idea how to do that .