Computer crashes; can't decide what the faulty part is

[TheCowness]

I recently built a computer for the first time, but I've been having periodic crashes; about one or two a day. Everything works, it's just not stable. I've run Memtest twice without any errors, and I've run Prime95 on the Small FFT test for a few hours without any threads crashing, but if I run the other two Prime95 tests (large FFT, blend), it does start throwing math errors and crashing. It's not overheating unless this tool lies to me; I've never seen the CPU above 37 centigrade. I'm not overclocking or anything, and don't know much about doing that, so I don't really know what to tweak to try fixing it.

OS: Windows 8 Pro 64-Bit
CPU: AMD FX-8350
Graphics: Sapphire Radeon HD 7870
Motherboard: ASRock 970 Pro3
PSU: APEVIA ATX-CB700W
RAM: 2x 4GB Kingston HyperX DDR3 RAM
Drives: 250GB Kingston SSD, 1TB Hitachi HDD, 80GB Hitachi HDD, LG BD/DVD-RW
Coolermaster case with improperly installed Corsair H100 liquid cooler (It's mounted on the CPU right, but the radiator wouldn't fit with the stock fans, so I stuck some smaller fans in it but obviously couldn't mount them right. I don't think I'm having overheating issues though.)

Anyone have any ideas what else to test, or what the problem could be? Thanks in advance.

Edit: Added PSU to spec list

 

[swifty_morgan]

I really doubt the /rocessor never gets above 37c.

ull the water cooling, install the stock heat sink and fan.

if you have the o/erating system installed on the SSD disconnect the other hard drives.

my "tinkle" key doesn't work, sorry.

 

[jnkweaver]

What is your power supply? make and model.

 

[smorizio]

did you make sure your mb bios is up to date so it has the newest cpu and ram code??

 

[TheCowness]

Knew I'd forget something. PSU was this guy: http://www.newegg.com/Product/Product.aspx?Item=N82E16817148046 (APEVIA ATX-CB700W)

RAM was this: http://www.amazon.com/dp/B0057Q4ADU/ref=pe_175190_21431760_M3T1_SC_dp_1 (Kingston Hyper X Blu 8 GB (2x4GB Modules) 1600MHz DDR3 Non-ECC CL9 XMP Desktop Memory - KHX1600C9D3B1K2/8GX )

Pretty sure I've updated my BIOS, but I'll check.

Also, I don't believe the temperature either, but I used to have the stock heatsink on it and it still never got too hot. I'll try finding a different program to tell me my temps, but maybe the thermometer is just bad. Does that happen? Still, I can keep it running Prime95 and it'll sit at the highest temperature it reports the whole time without overheating or crashing.

 

[jnkweaver]

Next time instead of sorting on lowest price sort on best rating. The customer ratings is what makes Newegg so nice to use. I suspect it is your power supply. If you have another one around I suggest you test it. I don't have the whole list of reputable manufacturers but a few are Seasonic, Antec, and Corsair.

 

[jerry6]

that psu could be the problem , really not good. why buy good parts cpu , vga, and cheap out un the psu ?

 

[payturr]

You never ever EVER cheap out on your PSU. It is the heart to your computer - always buy name brand.