Vista OOM fix:Must have update from the mother-ship
Aug 28th a fix became available for Vista from the Windows team.
The bits will be made generally available from the link here and relatively detailed KB is attached.
The issue is that Vista was creating an extra copy of graphics memory ( noted by AnandTech here ) and that was causing a pre-mature exhaustion of each process's address space and then the dreaded OOM error. AnandTech reviews this issue further and tests the hotfix here.
Run, don't walk to this download.