We first reported on the Q815227 update for Windows XP on Sunday, where a program that uses large mapped file views to share information between two processes may experience a significant performance decrease on Intel Hyper-Threading capable CPU's. In the meantime a lot has happened on the Windows XP knowledge base article site. The article has been updated this Monday, June 16th. There is no change content wise, however Microsoft has siginificantly downgraded the file version numbers within the patch. While the original article stated the patch would upgrade the kernel files to build 1202, it now shows build number 1178 to be included. Kinda strange if you ask me. Read more...

The initial Sunday article also revealed that the file compile date would be April 8th, 2003: Date Time Version Size File name Platform
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08-Apr-2003 07:16 5.1.2600.1202 1.896.448 Ntkrnlmp.exe i386
08-Apr-2003 07:16 5.1.2600.1202 1.952.256 Ntkrnlpa.exe i386
08-Apr-2003 07:16 5.1.2600.1202 1.924.096 Ntkrpamp.exe i386
08-Apr-2003 07:16 5.1.2600.1202 1.928.832 Ntoskrnl.exe i386
08-Apr-2003 07:16 5.1.2600.1202 5.827.968 Ntkrnlmp.exe ia64
08-Apr-2003 07:16 5.1.2600.1202 5.738.368 Ntoskrnl.exe ia64
If you take a closer look on this Monday, you will see this: Date Time Version Size File name Platform
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28-Feb-2003 16:17 5.1.2600.1178 1,895,424 Ntkrnlmp.exe i386
28-Feb-2003 16:17 5.1.2600.1178 1,951,232 Ntkrnlpa.exe i386
28-Feb-2003 16:17 5.1.2600.1178 1,923,584 Ntkrpamp.exe i386
28-Feb-2003 16:17 5.1.2600.1178 1,927,424 Ntoskrnl.exe i386
28-Feb-2003 16:17 5.1.2600.1178 5,826,432 Ntkrnlmp.exe ia64
28-Feb-2003 16:17 5.1.2600.1178 5,736,704 Ntoskrnl.exe ia64
A download with the 1178 kernel build is available from Neowin I will try to investigate what happened to 1202. Update #1: If you do a search in the MS Knowledge Base for 5.1.2600.1202 the Q815227 article get's listed.