I recently built the system outlined in my signature but have suffered occasional random restarts while playing Left 4 Dead 2. I've played Fallout 3 and experienced crashes but they could well be coding errors (Windows continued to run underneath).
So far, errors have been found when testing the CPU and also the RAM, but I'm not sure that you tell that one hasn't caused an error in the other. Indeed, perhaps they are both faulty.
CPU tests:
CPU: LINPACK - ERROR after 13 minutes (max temp. 63 C)
CPU: OCCT - No error after 1 hr at default settings (max temp. 64 C)
CPU: OCCT - ERROR after five minutes at Test Mode: Large data set (max temp 64 C)
GPU tests:
GPU: OCCT - No error after 1 hr (I see no temperature readout for my card)
Furmark - No error reported after 4 hrs (I'm not sure how Furmark reports errors or whether it detects artifacts; max temp. 81 C)
RAM tests:
Memtest86+
WallTime: 12:33:59 - Cached: 4087M - RsvdMem: 12K - MemMap: e820 - Cache: on - ECC: off - Test: Std - Pass: 14 - Errors: 107 - ECC Errs: 0
Test: 4 - Pass: 0 - Failing address: 000bd7f3f3c - 3031.9MB - Good: fbee1d66 - Bad: fbee1d67 - Err-Bits: 00000001 - Count: 1 - Chan: [BLANK]
with settings: RAM: 800 MHz (DDR1600) / CAS: 11-11-11-24 / DDR3 (64 bits)
The memory is being run at its rated clock speed with lower-than-rated timings (it is supposed to be 7-7-7-24). The voltage supplied is 1.65.
Notice that the Errors readout is 107 but only one error is elaborated upon below it. The Errors readout is increasing with time.
Edit: tested again with settings: RAM: 533 MHz (DDR1066) / CAS: 7-7-7-16 / DDR3 (64-bits) @ 1.5 volts with result:
WallTime: 1:22:59 - Cached: 4087M - RsvdMem: 12K - MemMap: e820 - Cache: on - ECC: off - Test: Std - Pass: 1 - Errors: 4 - ECC Errs: 0
Test: 4 - Pass: 0 - Failing address: 000bd7f3f3c - 3031.9MB - Good: 2a9dc386 - Bad: 2a9dc387 - Err-Bits: 00000001 - Count: 1 - Chan: [BLANK]
Do I have problematic settings, CPU or RAM? Should I obtain an RMA on either component? Please advise.
You are overheating your components
If this is caused by the "test" you mentioned, I recommend you stop testing it...Is this one of those computer stress tests?
In any case, 64 C on the processor and 81C on the Furmark is medium well indeed!
There is a severe case ventilation problem?
The fans are not running?
Try taking the side off the computer case and run it
Whats the temp now?
(I don't run the stress test software, I don't recommend you do that.)
Over heating will severely shorten the life of the components and destroy them eventually.
You need front intake and rear exhaust fans, power supply fan, large CPU cooler...to run what you are trying to run, or maybe just a much better case with much better fans?