Long working PC suddenly freezing; looking for further troubleshooting

[sam1122922226737]

Here are my specs: speccy
OS: Windows 10 Pro 64
CPU: AMD FX-8150 not OC'ed
Mobo: Gigabyte Technology Co., Ltd. GA-990FXA-UD3 (rev. 1.0)
RAM: Corsair 16 (4x4) GB DDR3
GPU: 2x AMD Radeon HD 6850 (crossfired, I know speccy says they're not)
SSD: 64 GB Crucial M4 (backup)
250 GB Samsung 850 EVO (OS, installed when I upgraded to 10)
250 GB OCZ Vertex 4 (Games)

Hey guys, I have been having problems with my PC suddenly freezing for no apparent reason. My PC is ~4 years old and has not happened until the last 2 weeks. It happens pseudo-randomly; it seems to not happen when system is idling that I've seen, but it has happened while I've just been browsing the internet or watching a movie from my HDD. I have noticed, though, that it's more likely to happen when I'm playing games. In addition it might happen then more often when I use a lot of memory/CPU at once, e.g. Planetside 2 map changes, although that might just be confirmation bias.

My temps seem fine, the CPU is around 10C at idle, and rarely if ever goes above 50C even after a few hours of Prime95. The temp at the time it crashed most recently was 45C, well within the guidelines. I have 10 case fans (8x120, 1x140, 1x200), although 7 of them run off the CPU power header on my MOBO so they don't spin 100% basically ever. I have seen the temps in speedfan (the temp 1, temp 2, temp 3) spike up to 50C before, but I'm not even sure what temps they are measuring.

I've had Windows 10 installed since it became available and this problem didn't start until 2 weeks or so ago. So although it's possible that it's causing the problem, I would rather not clean install unless I have a reason to.

My event viewer is of no help, as I have to force it to shutdown by holding the power button; as there's no system response doing anything. No other critical or warning errors that correlate to the shutoffs.
I have updated drivers.
I've been running BIOS version 10a (current version is 10e) since I built the computer so I doubt it would be causing problems now.
As far as I know all my firmware is updated (checked rigorously on the new SSD, backup SSD)
I ran memtest for 8 passes with no errors.
I swapped out my PSU and even my case to see if it would be fixed to no avail.

Basically, I've run out of ideas! Is my mobo/cpu bad? What should I try?

Thanks in advance for your replies!

 

[capt_taco]

Here are my specs: speccy.txt
OS: Windows 10 Pro 64
CPU: AMD FX-8150 not OC'ed
Mobo: Gigabyte Technology Co., Ltd. GA-990FXA-UD3 (rev. 1.0)
RAM: Corsair 16 (4x4) GB DDR3
GPU: 2x AMD Radeon HD 6850 (crossfired, I know speccy says they're not)
SSD: 64 GB Crucial M4 (backup)
250 GB Samsung 850 EVO (OS, installed when I upgraded to 10)
250 GB OCZ Vertex 4 (Games)

Try setting the voltage and timings manually in the BIOS. With four sticks, sometimes the motherboard's "auto" settings fall apart and cause these kinds of freezes and crashes seemingly at random.

If you still experience the problem, raise the DRAM voltage by a touch - 0.02V or so, and if that doesn't work, 0.04-0.05V. If that doesn't work, don't bother going higher; the problem is likely something else.

Another way to check whether it's the four-sticks RAM problem is to run it with only two sticks for a time and see if the problem still crops up.

 

[sam1122922226737]

I upped the dram voltage to 1.65 as the corsair website recommended (my mobo had defaulted to 1.5V) and all the freezing disappeared! Gracias senor.