Complete freeze after RAM replacement

Today I replaced a single 8GB RAM stick with a 4v4GB RAM kit. Twice now, I have had a complete computer freeze (requiring reset button) while playing Guild Wars 2. I'm unsure that it's the RAM's fault, but I have a few reasons to believe so.

FX-6300 (OCed to 4.5 GHz. It was stable, but after swapping ram, I had to redo the OC in the BIOS because it reset itself with the new hardware. I may have forgotten to change some settings, causing an instability. I'm testing now)
Gigabyte GA-990FXA-UD5 mobo
GTX 760
Thermaltake Toughpower 750 gold
The RAM: was Partiot Viper Xtreme 8GB is now Gskillz 4x4GB.
NOTE: Both say they are 1600 on the sides, but I noticed the Gskillz kit says 1333 in the BIOS. I ignored it at first, wanting to see if I'd notice a problem (and this may be that problem surfacing now). Also note that the 4x4 kit has already been used in another computer I have here and so I know it's ok. Maybe incompatibility? Maybe bad BIOS settings with the CPU OC or RAM frequency as said above?

So far, I haven't been able to find any useful info in the Windows event viewer.

EDIT: I suppose I should form a question to help my readers with. 1, what's with this 1600MHz RAM showing up as 1333 in the BIOS? 2, if this does sound like a RAM issue, what do I need to do to fix it?

Go into the bios and set the RAM to 1600MHz. Check to see if the voltage and timings are right (the same as on the spec) after changing the frequency.

I didn't do this initially because, correct me if I'm wrong, wouldn't it make it difficult just to boot the comp if I ****ed up?

Nope. If it won't boot into windows after, just go back into the bios and change it back.

So it won't fail to boot into the BIOS if I tamper with RAM settings? That's relieving, it's the one thing I haven't messed with before. Why do you think it is registering as 1333 though? It says 1600 everywhere else, the website I got it from (Newegg), the invoice, the RAM sticker itself...

Someone correct me if I'm wrong, but It just tends to default to that frequency with the 6350.

When you're in the bios, look for a setting called 'AMP profile' for the RAM. It's the AMD equivalent of Intel's XMP profiles. It automatically sets the RAM to its stock settings.

It might fail to boot into BIOS. But it's not a problem. If that happens you just need to clear RTC RAM. There is a jumper for that on your motherboard. Read your motherboard's manual.

Manually setting it to 1600 caused a boot failure for Windows. The voltage is actually where it should be according to the RAMs spec, 1.5V. There was a profile thing there, I don't think it was "AMP" though, I forgot.

And yes, I figured jumping it would fix that but I wanted to be sure so I didn't have to spend the time guessworking that.

There was actually an XMP profile in there. Turning that on fixed the boot problem. I'll be doing tests to make sure everything is stable now. I think the problem with those freezes was caused by 1333MHz RAM being bad for my 4.5GHz CPU OC, but that's only speculation. I'll come back to this thread if testing shows more instabilities.

Another freeze, this time while prime95 testing (mixed). Windows event viewer shows nothing. The freeze happened at 1:29 and there's nothing in the event viewer with that timestamp. But, again, it's a freeze that I had to system reboot to get out of. I have a migraine and I'm tired, I'll have to try to fix this after a nap. Any comments in the meantime are appreciated.