I have the same issue.
the only thing I noticed was an error message in the XP64 logs
Event Type: Error
Event Source: Windows Search Service
Event Category: Gatherer
Event ID: 3083
Date: 28-04-2009
Time: 00:40:52
User: N/A
Computer: BEAST
Description:
The protocol handler Search.Mapi2Handler.1 cannot be loaded. Error description: Class not registered
.
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
I have a system that play's very well but sometimes , not often , CTD.
And it's not video card related, I can play at 1900x1080 with full specs...