Got this strange problem with my system...
Intel E8400 (Not overclocked)
Corsair XMS2 DDR2 800MHz 4x1GB
Galaxy EN8800GT 512MB
Windows XP Pro SP3
Anyway, i was trying to upgrade my memory from PC6400 800 to PC8500 1066MHz (same capacity e.g. 4x1GB) . But unfortunately encountered stability issues using 1066MHz, erratic Hanging on either BIOS , Windows Startup and even doing normal stuff on windows (e.g netsurfing, downloading, etc...) Tried running memtest on PC8500 memory (one at a time, then all connected) but it all passed (on at least 2 passes).
And when i placed back my PC6400 everything runs normally again (i.e. no instability). I've searched through Corsair knowledgebase but could not find same scenario.
Has anyone experienced this problem/s? Was it solved? Any ideas where to check next after memtest?