The SMPS detail eludes me but those 9600 video cards are getting a little old. Did you try replacing the heat sink compound on all heat sinks?
And how about using a single card?
Before I describe my problem, I would like to present my computer configuration
Assembled by cyberpowerpc
-Intel Quadcore 2.66 GHz Q9450 - liquid cooled
-8 GB (2 x 4 GB) Corsair RAM
-EVGA nforce ultra 790i motherboard
-EVGA NVidia 9600 GT 1GB graphics card x 2
-System HDD - 74GB WD Raptor 10000 RPM
-Windows 7 64 bit OS
In the last couple of weeks, my computer would freeze up after a couple of hours or even after four hours or so. The entire screen would freeze and the sound would freeze. I would be forced to restart it with the reset button. It would often not reboot after taking a long time to perform the bios check of memory and HDD etc., mentioning that either the boot manager was corrupt and I should use the installation disk to fix the problem or it would mention that some USB device was removed or inserted.
In any case, if I waited for a while and then switched on the computer later, it would boot up normally after running a normal bios check. I thought that this could be due to over heating of the components. So I opened up the system yesterday and found that the fan on the graphics card had fallen off. So I reattached it.
Now, I have a new issue: The entire computer just randomly shuts down as if there was a power outage. There are no warnings, no errors presented. When I restart, it would again shut down after the bios check when it tries to boot windows.
When I shut it down completely (turned of the power switch of the SMPS unit) waited 10 secs and then turned everything on, then it started fine.
I would be very grateful to anyone who could provide insight into this issue.