Various random BSODs, usually when doing light activity

I've tried multiple slots, with both ram sticks together, and individually - I get BSODs with whichever. No Memtest errors though.

My understanding is that the memory controller is on the CPU now, which could well implicate the CPU also.

Passed 10 passes at Very High level. Max temp 65ºC.

The major difficulty I'm having working this problem out is that I can't get an error in any testing software, so it's hard to nail down.
The other problem is the infrequent nature of the BSODs, sometimes not occurring for 2 weeks.

I'm going to format Win7.

Thank you for your help.

Well,

I continue to have the same issues.

Still getting BSODs, mostly Memory_management.
But much frequently getting problems either going in to sleep, or resuming from sleep. Sometimes hangs / black screens, more frequently a single program will crash. Can be firefox, thunderbird, my password manager, solidworks, anything really.

I've run Memtest86+ (previously used Memtest86) for 24 hours on single core, and then 24 hours on parallel (all 8 cores) without any errors. (Using my 16gb RAM)

I've run for a few weeks on entirely different RAM (2x2gb sticks) - possibly had less BSODs, but still had some and still had programs crashing, particularly when resuming from sleep.

I've reinstalled Windows 7 a number of months ago.
I've updated to the latest BIOS.
I've tried various versions of AMD graphics drivers.

I would happily buy a replacement part if I could work out which part needed replacing!!!