There had been mentions in the past that SP1 degraded system performance for some people. There was a fix released (Q815411) but it's not publicly available and I think it doesn't address the problem sucessfully.

I am using a Windows CD with SP1 slipstreamed into it and I would like to know more information on this subject. Is the SP1 slowdown real? Which users/software/hardware does it affect? Is it severe? And, is there no solution so far other than to avoid SP1 altogether?

If you have that problem like i did and you cant find the fix for it dont use SP1 or your computer will get very slow.

I just installed SP1 with my installation CD that I oredred and on the reboot I had the fastest boot ever. The little squares passed by only 3 1/2 times before it dissapered. I recieved it 4 days ago and installed it yesterday.

i also encoutered this problem. Did microsoft announce the reason? any solution?

[17:09] -LordGoth:#winxp- sp1slowdown == Yes, *some* apps may launch 'up to 10 times slower' after applying XP-SP1. Read about it here --> http://support.microsoft.com/?id=kb;en-us;815411 || No, they won't give you the file, but we have it available here --> http://home.cwru.edu/~bwm3/Q815411_WXP_SP2_x86_ENU.exe (~550KB)

there u go

the only file this speed-patch is updating is ntdll.dll that hast the version number 5.1.2600.1177

the ntdll.dll in the "kernel rollup hotfix package" (http://support.microsoft.com/?kbid=820128) got the version number 5.1.2600.1221

so i huess this speed-issue should also be gone with this patch? or am i wrong?

Actually, if the file is not publically posted, it only takes a phonecall to your local Microsoft Support number, then they will mail the file to you within 4 hours....

At the end of the Knowledge Base Article:

Note This article was revised on 4/12/2003 to more accurately reflect the specific purpose and details of the fix. The original title of this article gave the false impression that this was a problem facing many, if not most, Windows XP users who installed SP1. In fact, the problem affects a very small number of customers who are using a privately designed program that exhibits behavior that the hotfix was created to address. (This article was previously published under the title: “Programs Run Slower After You Install Windows XP SP-1”. The contents of the hotfix itself have not changed, only the Knowledge Base documentation was revised for improved accuracy and clarity.