Microsoft Confirms Bug in Hyper-Threading for Windows XP SP1

Warp2Search picked up on the fact Microsoft have issued a KB article describing a bug in Intel's Hyper-Threading technology for Windows XP SP1. According to the article, a program that uses large mapped file views to share information between two processes may experience a significant performance decrease. The performance degradation occurs in the UnmapViewOfFile function.

This problem occurs if you install Windows XP Service Pack 1 (SP1) on an Intel Pentium 4 computer that has more than one logical processor.

Updated: The kernel files are supposed to be updated to version 5.1.2600.1202 once installed. For reasons unknown to Neowin currently, the files are updated to version 5.1.2600.1178. We're investigating this and we'll keep you updated.

Updated again: Microsoft have ammended the KB article and it now correctly reads the files should be updated to version 5.1.2600.1178.

The update isn't available generally over the internet, however you can phone Microsoft support or download it from the link we have provided below. Take care when installing this HotFix on your system.

DL: http://homepage.ntlworld.com/creamha...P2_x86_ENU.exe ( But this is not the MS site ?? )
MS Site:http://support.microsoft.com/default...b;en-us;815227
News source: http://www.warp2search.net/article.p...rder=0&thold=0

Well, this is great... I am supposed to be getting in an Intel P4 3.06 for my rig tomorrow...

Has anyone experienced this bug? If so, did you install the patch Q815227 - did it resolve the issue?

Thanks for the info Alpine!

-SlickVic78

@Slickvick
I think you have to have "2 logical processors" in order for this to happen. By 2 logical processors, I think they mean dual CPU.

What is a dual Logical processor. I have a Dell 8200 with a pentium 4 processor. Does this download concern me? Thanks.

Some "heavier duty" motherboards, like those for servers, have two or more processors on them. I'd love to have 2 - 3.06GHz P4 chips in my system. Woo hoo! :D

Dual cpu - the mother board allows installation of 2 proc of the same specs... eg. P4 3GHz x 2, the stepping and cache also needs to be take care of. if mix with P4 3GHz and a P4 2.4GHz, then the boot won't work.

and by having dual cpu does not means that your system will be any faster....... if a certain supports or has the capability with dual cpu, then u will see the difference..... booting up wise, i dun tink u will feel it..... cos i work with a dual cpu machine b4....

thanks

Hey billybob3,

Whew! Thanks for clearing that up for me... I feel better now! :)

Can't wait to drop the P4 3.06 into my rig... I would have kept my P4 2.53, but I was presented with a pretty nice deal on the P4 3.06 brand new - why wouldn't I take up on the offer?... :D

-SlickVic78

NP Slick! :D