ASRock Z68 Pro Gen3 Issues?

Hey guys, my rig is :

Intel i2500k
cooler- COOLER MASTER Hyper 212 EVO with arctic silver compound
ASRock Z68 Pro Gen3
G.Skill Ripjaw X 8gb (2x4gb) model F3-12800CL9D-8GBXL
Evga 560ti
Thermaltake Toughpower 775w
Western Digital Black 1tb hdd
Windows 7 Pro x64

I am having issues where the pc is freezing up, while it is frozen it repeats the split second audio that was playing in a loop. I noticed the display driver would crash if it froze for a longer period of time and my msi afterburner would show at/around the point of freezing that the gpu would have erratic usage from 0-6% for about 4seconds. Sometimes instead of freezing the display driver might crash multiple times in a row. Sometimes I may not even be doing anything on my pc, not even surfing the internet, I just notice the crashes and display driver crash message from afar.

I am rma'ing my gpu because of this, but I notice just running off the 2500k's gpu I still sometimes get slight freezes still. No driver crashes, also it seems to happen much less often than when I had my 560ti plugged in.

Overall these freezes seem to be extremely random and I can't seem to recreate a freeze or tell when it is going to happen. When the 560ti was plugged in I noticed more freezes while in browser and fewer when in game but that could just be because I'm in browser more often. Also the only game I noticed artifacts in was bf3.

I ran memtest for a few passes and found 0 errors, I tried using my old 600w psu and still had freezing and I doubt it is windows or my HDD since I did a fresh install of windows when I made this pc with my old hdd and my "old" hdd was rma'd only a few months ago because the last one was clicking after a year or so. Also temps are fine, I use custom 560ti fan profiles, and the coolermaster hyper 212 with arctic silver compound.

Also a slight sidenote, I notice if I press the delete button multiple times at bios post to get into the bios setup sometimes my system just hangs where I have to restart.

Could this still be a ram issue even though memtest found nothing? I am hoping it isn't a mobo problem since taking it all apart and putting it back together wouldn't be fun while finals week looms.

Thanks,
~Joe