Yesterday, Microsoft released a hotfix download under the code KB2592546. Not 24 hours passed, and Microsoft pulled down the patch due to unforseen problems.
Less than 24 hours ago, under the code KB2592546, Microsoft released a patch titled "An update to optimize the performance of AMD Bulldozer CPUs that are used by Windows 7-based or Windows Server 2008 R2-based computers is available".
As we reported previously, this kernel hotfix properly detects the Bulldozer processing cores, which was not the case since the product launched. Bulldozer CPU architecture is closely tied to optimizing the Turbo mode as much as possible, and Windows XP, Windows Vista and Windows 7 don't recognize the FX and Opteron processors as they are supposed to. Do note that 2012 operating systems such as Windows 8 and Windows 8 Server already built-in the proper threading scheduler.
According to Microsoft, this patch increases performance anywhere between 2-7%, which is not bad for a software update. However, upon releasing the update into the wild, there were users that reported problems and even performance decrease. In order to address the matter, Microsoft pulled down the patch.
The KB2592546 page is still live on Microsoft Support, and it states that there is a "hotfix download available." If you try to download the patch, you will be taken to the EULA page in which you give permission to "sell your soul" and proceed. Unfortunately, the next page is not going to give you what you came for. As you can see on our screenshot – the patch simply isn't there anymore.
We will follow the situation and report when the patch comes back online.