Okay. I traced the problem as well as I could...
It's not the power supply, processor, memory, or motherboard...
It's either the drive the games are running from, or the GPU's. And I think it's the GPU's.
Today I got a BSOD, but I didn't have enough time to view information about it. Also, my computer is in the middle of being put into another case, so I can't exactly look it up, but I will provide some information:
The problem occurred, as stated in the first post, while gaming. My computer shut down, and upon restart there was a BSOD that was on screen for about 3 seconds. The computer shut off then restarted. I decided to try something different.
I took out my bottom graphic card, and played from a single card. Everything ran pretty well, I was actually impressed with the performance of my single 6950 at 1080p. After about an hour and a half, I quit the game, and checked the temperatures. All the components were out of the case at this time, but the GPU was VERY cool. After an hour and a half of running Crysis 2 on Ultra at 1920 x 1080 (I would estimate averaging 50 FPS, maybe more) the GPU was only 38C.
I then turned off the computer, and swapped out the one in there for what is usually my bottom card. The first thing I did was try to check idle temperatures, and to my surprise I was not able to register any temperatures. I found it odd, but thought it could have been caused by anything. So, I loaded up Crysis 2 at the exact same settings and played the exact same level I did on the first card. With this other card in, performance was MUCH, MUCH lower. Around 30 FPS, or sometimes even lower down under 20. The game and computer never crashed/froze/shutdown, but this did get me thinking it's probably that card after all.
So, I think I'm going to send that card back. I'll update on the status once my replacement card comes in, on whether this was truly the issue or not.
I will note; neither cards are, or were ever, over-clocked. The second card never seemed to read/work right in the first place, but I never suspected it because I guess I'm an idiot.
Even in Catalyst Center, it would always say there was 0 power given to the card, no temperature, and no "activity" coming from the card. Hopefully, this fixes my issue.