On Thursday, December 15, MS released a hotfix to “optimize the peformance of AMD Bulldozer CPUs…” for Windows 7 or Windows Server 2008 R2 (KB2592546). Seems that the original code base wasn’t properly set up to take full advantage of multi-threading in the Bulldozer architecture. According to some hurry-up benchmarking work from X-bit Labs, the hotfix could boost performance anywhere from 2-10 percent, depending on the actual application involved — but only if that application is designed to run in multi-threaded fashion.
This morning, however, VR-Zone posted a story entitled “Microsoft Pulls Down the AMD Bulldozer Multi-Threaded Patch,” citing reports of user problems and peformance decreases for the reversal in course. While you can visit the Hotfix page for KB2592546, you’ll immediately notice that the download links on this page are no longer live.
I’m guessing that a development team is working feverishly to address whatever gotchas popped up following the inital drop of this release onto the Microsoft Support pages. I imagine we’ll see a round two on this stuff as soon as it’s judged to be “really working this time.”
[Note on 12/19: HardOCP has since explained that the initial hotfix was incomplete, and got pulled because it demonstrated a negative effect -- that is, decreased performance -- on enough Bulldozer systems that MS apparently decided it was better off pulling the code than leaving it up for download.]