WinXP + SP1 = 56% CPU Usage @ Idle?
Shortly after installing SP1 on WinXP Pro I noticed a few games were running a bit choppier, also a slight keyboard lag.

I didnt pay much attention to it because I had changed around some video drivers and agp drivers around the same time. After browsing some Warp2Search forums (http://www.warp2search.net/forums/viewtopic.php?t=982)

I came a cross this. I checked my CPU Usage and sure enough, 56% and my computer was idle.

This explained why Madden 2003 kept jolting at times, and why i couldnt kick a good punt (Cause you need good key timing to get the guage in the power bar, and the slight lag was messing that up)

I did some service tweaks, and no help.

I noticed my IDE HDD Controller reverted back to a MS version. Previously I had the Via 4-1 Controlling this. I reinstalled the 4.43 4in1's manually. Removed the SB Audigy Drivers (suspected component) and updated my Nvidia Drivers (Surely not related to the problem) And now my cpu usage is back below 5% when idle.

I replaced the Audigy drivers with the Kx Beta Sound Drivers. Im sure its the ide controller, but the sp1 service pack DID change other drivers, like using a microsoft Geforce2 driver.

If you have this problem, I suggest you reinstall 4-1s MANUALLY (4.43 does not install through setup) reinstall video card drivers, ide controllers/raid controllers, and sound card drivers. I keep all of the above in my /Drivers folder so I wont have driver conflict if I accidently install an older version.

Best way to check your CPU Usage in XP if you dont know is CTRL + ALT + DEL and click on the performance tab.

However, it might be a good idea just to check up on your driver versions and make sure its all legit

And remember, when it comes to computers....what works for one person, doesnt mean its going to work for the next person.

*Another thing people have said is if you have a ATA133 hdd, it reverts it back to PIO mode for whatever reason.
taken from:
THIS SITE

news source: warp2search.net

Enjoy,
BB