New rig: random freezes and BSODs

Hi there,

I'm currently investigating issues with my new computer, and I can't really pinpoint them. Funny thing: it works great in Linux, but not in Windows (dual boot). Windows failures seem hardware-related; Linux might be more fault-tolerant or something, but I'd better fix that before things get ugly.

So here's the hardware I have:
- CPU = AMD FX8320
- GPU = Gainward Phantom Nvidia GTX770
- RAM = G.Skill RipJaws 2x 4Go DDR3
- Motherboard = ASrock 970 Pro3 R2
- PSU = Antec Eco 620C
- HDD = Toshiba 2 To
- CPU cooling = Seidon 120m
- Windows: Win8.1 64bit
- Linux: Lubuntu 13.10 64bit

I've built this machine about one month ago, but a few days ago did I decide to install Windows on it in order to play a few more games in my Steam Library. While most games run mighty fine, I started to notice some weird behavior: the system tends to reboot on its own when left idle downloading Steam games, while it had no uptime issues in Linux. I tried throwing some stuff at it to stress-test the machine, and had a weird result with (only one out of the three available) Just Cause 2 benchmark, as seen here: https://www.youtube.com/watch?v=CPCXDuLAsSo

More investigation lead to more strange stuff, including the results of comparing Unigine Heaven on Linux and Windows using the same exact machine: https://www.youtube.com/watch?v=M6uAc7PtT2Y

I started to suspect the GPU, tried a Furmark burn-in test: no issues at all using the default 1080p 15 minutes benchmark. Besides, I got no issue in most games.
I wanted to make sure the RAM wasn't at fault, so I did a memtest run on each module, and a run with both modules: no errors.
I checked my hard drive, its SMART report says it's healthy.
I tried running OCCT and Prime95 on the CPU and, oh boy, it doesn't seem pretty: http://imgur.com/a/0wJZu

I found some puzzling Windows Events logs:

Code (Text):

1. LiveComm (3460) C:\Users\Me\AppData\Local\Packages\microsoft.windowscommunicationsapps_8wekyb3d8bbwe\LocalState\LiveComm\bd2f995a49f7b7a1\120712-0049\:
2. A request to read from the file "C:\Users\Guillaume\AppData\Local\Packages\microsoft.windowscommunicationsapps_8wekyb3d8bbwe\LocalState\LiveComm\bd2f995a49f7b7a1\120712-0049\DBStore\livecomm.edb" at offset 7217152 (0x00000000006e2000) for 8192 (0x00002000) bytes succeeded, but took an abnormally long time (15 seconds) to be serviced by the OS.
3. This problem is likely due to faulty hardware. Please contact your hardware vendor for further assistance diagnosing the problem.
4.  
5. {Registry Hive Recovered} Registry hive (file): '\SystemRoot\System32\config\DRIVERS' was corrupted and it has been recovered. Some data might have been lost.
6.  
7. The following boot-start or system-start driver(s) did not load:
8. dam
9. EhStorClass
10.  
11. The nvUpdatusService service was unable to log on as .\UpdatusUser with the currently configured password due to the following error:
12. The system cannot find the file specified.
13. To ensure that the service is configured properly, use the Services snap-in in Microsoft Management Console (MMC).
14.  
15. The system has been constrained to a periodic tick. Reason: BCD override.
16.  
17. The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
18. Crash dump initialization failed!

So, err, what should I do from there?

 

I removed both RAM modules from my machine, and tried again with the only other one I had around - a 1gb DDR3 stick from my HTPC. I still get the exact same issues.
I haven't tested it the other way around.