Random system lock ups with games and video

I have recently built a new system with the following components:

evga 750i FTW mobo
quad core q9400 2.67
4gigs OCZ Reaper SDRAM DDR2 800 (PC2 6400)
evga 9800 gx2
Antec NeoPower 650W

When I first set everything up I started randomly getting system freezes with any game or video playback. The freezes sometimes occurred often( every 10 minutes ) but for the most part it will lock every couple of hours or so requiring a manual shutdown.

My initial thought was the graphics card so I exchanged it for a Zotac 260 amp2. The freezes still occur so my next thought would be the motherboard. EVGA suggested that it sounds like a Power supply issue or potentially my memory setup so I manually set the latency and voltage for my memory its recommended settings with no change.

the 260 says it requires 500watts and 36 amps. My power supply has the watts and it has 3 rails for 12 volt at 19 amps each. Is there some reason that the card might not be getting what it wants with this PSU? I also had a spare psu which I tried as well. It was similar in power but just another brand and this didn't change anything.

I have already reinstalled the drivers with the most recent multiple times unless there is something obscure that I've missed and don't know about.

Any help is appreciated!
Thanks

I guess I haven't checked the temps but when I open the case after a freeze it doesn't even feel warm in the case. Also when it freezes I can restart instantly and jump right back to the game and it may not freeze again for the rest of the day.

I can check the exact temps when I'm off work.

Yes the memory is new. I think that might be the next thing for me to try.

Ok I'll give that a try tonight.

Thanks for the help.

I recently set the settings in the bios to the proper latency and voltage.
4-4-4-15 and 2.1 volts. In the bios it was at 5-5-5-18 and 1.9 volts. This made my computer faster but it still has the problem of freezing. Could this have damaged the memory? When it was running at a lower voltage and lower latency shouldn't it just be safer anyway?

I ran memtest86 last night for 9+ hours and 5 full passes and I did not receive any errors. when playing COD4 for a short while my gpu temp wasn't over 55 and cpu was similar. I am now running prime95 to see if that finds anything.

What would be my next step if this passes?

Hi Klint,

At first I too was running at the default 1.8 and slower latency settings but i went in and changed the voltage to the recommended 2.1 and the latency to 4-4-4-12. I contacted tech support and that is all they told me to do as well. It still gave me the freezes but I have recently put some new memory in my comp and all problems are fixed.

Thanks for the reply
-Ryan