06.168.2003 - Microsoft Confirms Bug in Hyper-Threading for Windows XP SP1 (815227)

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. 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. - Download Q815227_WXP_SP2_x86_ENU.exe (Direct Link) - View Microsoft Knowledge Base Article - 815227 - Visit Microsoft Corporation