Top GPU not detected after being blocked

[Jojimbo]

So after having my PC sit around for months and then waiting for some new tubing I finally put my PC back together...and the top GPU (MSI) still isn't outputting video.

Had the same issue last time, I was hoping it was caused by the bent CPU pins that were also causing the corrupt BIOS and faulty DIMM slots but it turns out it's something else. The bottom GPU (Asus) is working fine, although it has this awful coil whine that sounds more like a rattling fan. I haven't plugged in the bridge yet so it's not a case of that disabling outputs on one of the cards.

Now the MSI GPU itself should be fine, between it not working last time and now I've used it on it's on in the top slot with stock air cooling and there was nothing wrong with it. However now that it's blocked and in the loop it is detected as running at x0 in the BIOS and does not output anything (while powered anyway, when unplugged it just says not detected). It still doesn't output if only it is powered and not the Asus.


I'm thinking either the backplate is shorting it, which would be weird as the Asus has longer points sticking out and is fine and I couldn't see anything touching, or the MB/GPU is faulty and only half of it is working (the half that is not used when using dual cards, if that's possible at all?). I only suggest the second option because when I tested in my old PC it was detected as running at x8 (it's an i7 920 + X58 so no x8 slots), I originally ignored this because I'm pretty sure it was detected as x16 when back in my Z77 but it might explain the problem.

The MB has been used for CFX before though, and I'm pretty sure with these two cards while they were both running on air but I'm not 100% as the MSI was a replacement for a second Asus that didn't OC well (and had a faulty fan) and I can't remember if I put them back in together or not before trying to water cool.

Any suggestions for what to look for when I take the loop apart (again)? I was going to start by just taking out the bottom GPU and trying the MSI on it's own with the block and if that doesn't work take off the backplate and trim the pins + raise the backplate with a couple of MB washers (kinda hoping I don't have to as the screws are kinda threaded so it might be a pita to take apart).

EDIT:: Forgot specs >.>

i5 3570k @ 4.4GHz
Z77 Sabertooth
8GB 2133MHz Patriot Viper 3
MSI 7950 + Asus 7950 with 2x Swiftech 7900 Komodo
Corsair AX860

 

[Wraith]

Bent pins, faulty Dimm slots, corrupt Bios and whiny coil noises....

Sounds about ready for silicon heaven.

 

[Bartacus]

Damn, that does sound rather dire. Silly question: any chance your PSU is acting up? Maybe try switching the power cables to the vid cards and see if that changes anything?

 

[Remmy]

Is it possible that while you were installing the waterblock you got any (conductive) thermal compound on anything you shouldn't, that could be shorting the GPU out? Or did you use non-conductive?

 

[Jojimbo]

I used MX-3, last time I had used Liquid Metal and pushed some of the original stock paste over but after taking the block back off/cleaning and testing it on air cooling it worked fine, and afaik I didn't get anything over the edge this time either.

I've tried both PCI-E leads for my PSU, I've even had my old AX850 PSU RMA'ed because it was making noises after I shut down my PC, my current AX860 also makes noises but intermittently and both while on and off =( Both of them had the same problem so I doubt it is the PSU.

 

[Bartacus]

Hmm, TWO PSUs making funny noises? That's very odd, and especially those units, since I believe both of those are rebranded Seasonics. You rarely hear about issues with those units.

Another dumb question: how's the electrical in your house? Any chance of a funky outlet that's either spiking or dipping in voltage? Shot in the dark I know, but these issues sound awfully weird.

Also, did you use the power cable that came with your PSUs? Or would you happen to be reusing an old one?

 

[Jojimbo]

Same outlet and surge protector (although I tried straight out the wall iirc), tried with and without an APC 1200 Line-R AVR though (thought this was the cause originally). They're also different noises, AX850 was only when PC is off, happened every time and only stopped when MB light goes out and AX860 is when PC is on or off, happens randomly and stops the instant I turn the PSU off.

Not many options for plug sockets on this side of the room though, and the wiring is probably so-so at best in all honesty. House is pretty old and not exactly in top condition.