Comment 24 for bug 196220

Sorry, is not a overclock issue. Unfortunately the issue occurs randomly when in xorg.conf I have:
Section "Device"
        Identifier "Intel Corporation 965 G1 Integrated Graphics Controller"
        Driver "intel"
        BusID "PCI:0:2:0"
        VideoRam 393216
        Option "AccelMethod" "EXA"
        Option "MigraionHeuristic" "greedy"
        Option "ExaNoComposite" "false"
EndSection

and also:

Section "Device"
        Identifier "Intel Corporation 965 G1 Integrated Graphics Controller"
        Driver "intel"
        BusID "PCI:0:2:0"
        VideoRam 393216
        Option "AccelMethod" "XAA"
EndSection

Bios setting for Integrated video card:
DVMT Mode Select -> DVMT Mode
DVMT/Fixed Memory -> Maxim DVMT (384 Mb)

How to for debug?
Thanks