Damaged 3770k or motherboard?

[scook9]

I have a watercooled i7 3770k sitting in an Asus Maximus V Formula (that is part of the same loop using the built in VRM cooling). The CPU has always been stock and the only overclock of any kind is the XMP profile on my Kingston Hyper-X ram to set it at the rated DDR3-2133. Last week I discovered that my pump (an MCP-355) had died. I do not know for how long it had been dead. The system is left on 24/7 so the CPU may have been sitting at a very high temperature for an extended amount of time.

I have 16GB of Kingston Hyper-X ram (4x4GB) and 2x EVGA GTX 670 FTW GPUs in this system.

I finally got the replacement pump installed (an MCP35x with heatsink to keep it from burning out like the last one) and started the system back up. I had assumed that the CPU has built in thermal protection so should be fine however I am seeing very strange behavior now out of the computer. With all 4 sticks of ram installed I get a 55 post code which is "memory not installed". I get the same code with 2 sticks installed if I set the XMP profile and do not leave it at auto. I tried both sets of sticks in both sets of DIMMs on the motherboard. Furthermore, I am seeing only one of my GPUs. Both in the BIOS and the OS even though both are installed. The one GPU that is showing up is only running at PCIex8 rather than the expected x16 if there is only one GPU installed. I will try some combinations of GPUs in various slots but currently it is clearly not working as expected.

Has anyone else seen any CPU failure like this where it appears the PCIe controller and the Memory controller may be damaged simply from extended periods of high temperature? As far as I can tell the system never rebooted itself due to heat but it was definitely hot.

Any help or suggestions for troubleshooting is appreciated - thanks!

[scook9]

So far, one GPU in top slot with nothing else installed showed up as PCIe 3.0 x16 as expected. With just one GPU in the 2nd slot the system would boot but I got no video output from the card. With both cards installed but the monitors connected to the 2nd card I get a normal boot but no video output - moving the monitors to the first card brings up pictures and the usual only one card installed. It is like the 2nd card is not there at all, the only way that I know the motherboard/computer knows it is there period is that it is switching the first card to x8 down from x16. Otherwise there is not a trace that it is installed in Bios or OS. I moved the PCIe power cables between cards in case that was it and it changed nothing.

And to add to the oddity, CPU-Z sees 4 separate ram sticks when they are all installed (with separate serial numbers) but the BIOS and OS only see 8GB installed.

[xpower]

very basic. thermal protection kicks in only when it reach to max Tj limit. you see any reboot or shut down with old pump installed? if not your cpu is fine. install cpu in another system just to make sure? mem not detect check cpu to full contact with the socket pins. any sign of old pump leakage?

[scook9]

Old pump was not leaking, just burnt out. I did an autopsy and part of the PCB is blackened - sounds like cheap chinese MOSFET is the culprit from reading online. I have purchased a 2nd 3770k and swapped that in and am seeing the exact same problems. I closely inspected the socket and nothing is bent or getting bad contact there. It appears that the motherboard is the point of failure, I will have to RMA it