Potential CPU failure

[Mortisfacio]

So recently my computer has been rebooting on it's own. I built the computer in early April of this year and everything has been fine until a few days ago when playing more graphic intensive games/rendering my art programs with cores unlocked I'm unable to go for long without my computer rebooting. Every about 4-5th crash my motherboard (ASUS M4A88T-M) MEM-OK button will continually flash and never post. Usually have to unplug the power supply for a few moments to get it to post. My power supply is well above what I need so I figure it can't be a wattage issue, also since I've made no upgrades to change things. However a quick run of prime95 will either immediately crash my computer or will do so within the next 20~ seconds leading me to believe this may be a CPU issue. Should I go ahead and look into trying a new CPU or am I not thinking clearly and it may be another issue?

Specs:
Motherboard - ASUS M4A88T-M
CPU - AMD Phenom II X6 1090T Black Edition Thuban 3.2GHz
GPU - EVGA 01G-P3-1371-TR GeForce GTX 460 (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16
HDD - Western Digital Caviar Black WD1001FALS 1TB 7200 RPM SATA 3.0Gb/s
SSD - Intel X25-M SSDSA2MH120G2K5 2.5" 120GB SATA II
Memory/RAM - G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600/Kingston ValueRAM 2GB 240-Pin DDR3 SDRAM DDR3 1333 (2 of each. 12gb total)
PSU - CORSAIR Builder Series CX600 (CMPSU-600CX) 600W ATX12V v2.3 Active PFC

Side note: Cores are no longer unlocked, although it's of no help at this point.

 

[FinneousPJ]

What cores are there to unlock on the Thuban? I'm confused.

 

[popatim]

What setting are you using for prime95? large ftt's typicall indicate a memory issue and small ftt's a cpu or motherbd issue.

 

[Raiddinn]

Why are all the RAM sticks not the same exact thing?

If it were me I would have picked 1 kind and got 4 of it, not 2 of each. RAM is cheap, get 2 more of the Ripjaws and get rid of the ValueRAM.

I also didn't think there were any locked cores on x6 Thubans.