GA-Z87-D3HP + EVGA 660 Ti Random freezing

[RL23]

I have a Z87-UD3H box with an MSI 650 Ti which is rock solid. My 2nd box, however, which is a Z87-D3HP with a 4770k (not overclocked) and an EVGA 660 Ti 2G is crashing randomly. No sign of anything in the logs, the system just locks up either when it is just sitting idle or when someone is doing something on it. No pattern to what causes it as far as I can tell.

I upgraded the bios on the motherboard from F4 to F6e which didn't change the symptoms at all. Very standard Mavericks using Multibeast DSDT-free setup. ALC-892 sound, Intel NIC driver, MacPro 3,1. Nothing unusual.

Chameleon settings:

        <key>EthernetBuiltIn</key>
        <string>Yes</string>
        <key>GraphicsEnabler</key>
        <string>No</string>
        <key>IGPEnabler</key>
        <string>Yes</string>
        <key>Kernel</key>
        <string>mach_kernel</string>
        <key>Kernel Flags</key>
        <string></string>
        <key>Legacy Logo</key>
        <string>Yes</string>
        <key>Timeout</key>
        <string>2</string>
        <key>GenerateCStates</key>
        <string>Yes</string>
        <key>GeneratePStates</key>
        <string>Yes</string>
        <key>UseKernelCache</key>
        <string>Yes</string>

I've done a memtest86 check and the 16G of memory passed, but I only ran it for about 20 minutes so I should probably do a more extensive test. Doesn't feel like a memory issue to me though. I think my next step is to yank the 650 Ti out of my other box and try it in this one to see if this is related to the EVGA card.

Anyone have similar hardware that works and/or have seen similar symptoms?

 

[RL23]

Looks like I solved this one. I noticed CPU temps were spiking (HWMonitor is awesome) so I took off the CM H60i water cooler and noticed that the pre-applied thermal paste had barely been disturbed and it was quite hard to the touch. Scraping it off and putting fresh paste on drastically reduced cpu temps under load.