Please inform us of the detailed configuration (eg motherboard / graphics / PSU)
GA-970A-DS3P mobo, 2048MB ATI AMD Radeon R7 360 Series (XFX Pine Group) VGA, EVGA 600W psu, 8.00GB Crucial Dual-Channel DDR3 @ 803MHz
You can try to see if the Windows Event Manager has saved some error codes. If those related error codes exist, you can go to Microsoft or Google to query the error code, you may get some clues to solve the problem.
You wrote on this topic, "Not long after I upgraded my CPU from a 6-core FX 6300 to an 8-core FX 8350", what changes have you made during this period of time? (eg overclocking / changing the memory clock, etc.)
And, you mentioned "I've changed mobo (same model), RAM, PSU, HDD & even clean installed Win 7 Pro x64 but the problems remains."
If you still have these accessories, I recommend that you set up a control group, use the same system, try to use the same accessories as possible, use your FX-8350 for testing, and document the results of the test.
In addition, you can try to update your motherboard BIOS, this may not work, but it may improve or solve the problem.
However, the worst result is that your CPU is faulty (I think the probability is low)
The only change I made was updating the CPU, everything else remained
the same; no overclocking.
The mobo has the latest BIOS. I used an Arctic A11 on both CPU's so
both CPU's remained cool (< 30°C)
When investigating the problem I only changed 1 item at a time & ran the
test until the 'freezing' problem occurred; which could be a matter of
hours or sometimes days! Since refitting the FX-6300 2 days ago the PC
When I say 'frozen' it's not that the PC locks but it's busy doing
something else so any actions I take join a queue & are performed when
the PC returns to normal?
I thought, like you, that CPU problems are very unusual but in this case
it appears to be the culprit.
I'll try raising an RMA with AMD & see if they can find any faults with
the FX-8350 CPU.
Sorry, I can't help.
But before RMA, maybe you can contact AMD Customer Support Center first.
See if they have any suggestions
When you changed the cpu, did you clear the CMOS and load defaults?
If not do it next time you change.
..and that's all I got.
Also, I hope you notice that the FX 6300 TDP is 95 watts.
And the 8350 TDP is 125 watts.
Please pay attention to whether the CPU has a high temperature problem.