No BSOD, white screen only!

Hello,

this is my first post,

just built a new machine with below spec, only additions are Office 2010, adobe, Microsoft security essentials.

Machine boots fine and will whitescreen after about ten minutes, when browsing internet, watching video etc, have to hold power to reset, then load back into windows normal selection,

All drivers are upto date from MSI, all windows updates applied.

It does this a couple of times and then seems fine.

Turn off and leave for a few hours and bang does it again for the first couple of times then fine again,

Thought PSU so upgraded to 650 watt 80+

Have done memtest for 8 hours on memory.

When not crashing will run OCCT for 3-4 hours no problem and did prime for 18 hours plus no problem.

Turned on when cold and white screened after 5-10 mins,

Have done disk check no errors found and runs furmark okay,

Im a bit baffled was thinking GFX card, possibly micro fracture?



thanks in advance any help welcome

John

Machine is not overclocked and have tried changing gfx drivers