Graphics card or motherboard?

[manamissam]

I have a self-built computer, and for the past several months, I have had a reoccuring error. My computer randomly shuts off a video signal and completely freezes (shutdown commands will not work), yet fans keep running and they will even sometimes speed up. Originally, I thought it was the power supply, so I bought a new one, but that did not fix it. This crash has occurred in the bios as well as during a memtest, so I know it's not a problem with the OS or hard drive. Is this more likely to be a graphics card problem or a dying motherboard? Or could it even be the processor? Thanks for any help.

Specs:

WD Black 500gb HDD
Crucial M4 64gb SSD
AMD Phenom II X4 955
HIS Radeon HD 6870
ASRock 870 Extreme3 Mobo
Wintec 4gb DDR3 1333 RAM
Corsair CX500 500-watt PSU

 

[cmi86]

It's definitely a hardware fault of some sort but it is almost impossible to help diagnose without further information. what you your error logs say ?

 

[manamissam]

well this comes up as a critical error every time it happens, I'm not sure what other information there could be.

 

[Scott_D_Bowen]

Your motherboard is an ASRock and you know it isn't the power supply...

Did it actually restart during a MemTest86+ run, or just freeze? (Either is a sign of a massive hardware defect).
- During the MemTest86+ did you get any memory errors?

... my money is on the motherboard personally.

- CPUs will last 25+ years and certainly no less than 8 years.
- A defective or failing HDD may freeze windows, but it wouldn't freeze an in memory OS (such as MemTest86+).
- Do you have a cheap/old video card that you trust?

 

[manamissam]

During the MemTest86+ run, it did the same crash as it did when it was booted into the OS. The monitor lost a signal, the fans sped up, and the computer became unresponsive. Even thought the memtest never got to finish, it had not come up with any errors. I do have an old graphics card that I trust, and it seemed to have worked when I put it in, but I feel like I can't be sure since the crashes are so random.

I have had minor problems with the motherboard before though, such as it not restarting properly or booting itself up on its own after being in hibernation mode.

 

[cmi86]

try the old CPU for a couple days and see what happens \

 

[manamissam]

It turned out to be the motherboard. I bought a new one, put it in without reinstalling windows, and everything worked as it was supposed to. Thanks guys.