NVIDIA 770 square and horizontal line artifacts before crashing
To start off my build:
Gigabyte GTX 770 4GB GSkill 4x8GB 1600MHz Cooler Master 1000W Silent Pro M Asus P8Z77-V PRO Corsair H100i i7-3770k @ 4.6GHz Dual monitor - Dell 24" IPS LED (secondary) and Samsung 24" S24B300EL (main monitor) Win7 Ult (64 bit) GTX PNY 460 1GB
This problem came about last night, I was browsing Reddit and watching Twitch when I get random green horizontal lines across the screen (thin, no pattern), I can't remember if just on my Samsung or both, and my computer restarts itself. At boot, there are the same horizontal green lines across the screen (through POST screens, windows logo, and on desktop). My first thought was the GPU, so I grabbed my spare GTX 460, but the same lines appeared. So I popped the CMOS battery (to reset everything) and booted using the integrated graphics, and no more green lines.
Since then I've fresh installed Win7 with my 460... which worked for ~20min after I updated the driver, then I get random colored pixel squares (about 50pixels square, kind of forming diagonals) and the graphics driver fails and recovers. Go about another 5 minutes, squares again, computer reboots. I switch back to integrated, no problems.
Now for the confusing part, I've never had an issue with the cards before, but about 2 weeks ago I had the 460 in my home server (just for a HTPC) and I got the same horizontal green lines. I removed it, thinking it was possible a driver error, and have been using my server's integrated graphics.
I have no reason to doubt my PSU, all voltages (as reported by the MB) were within tolerances (i.e. +12V was 12.094V). I did a Windows MemTest for the RAM, zero errors. I have not tested my Samsung monitor for errors (not sure how?), but with the lines only showing with the graphics cards, I think I can rule that out. My 3770k is very healthy, less than 6 months old. I did encounter some driver failures with my 770 a while back when I had it slightly (+75MHz) OC'd with EVGA PercisionX, but since then, I've underclocked the card by ~50MHz. I tried the graphics cards in both of the PCIe 3.0 slots, not in the 2.0 slot due to conflict with PSU, no change. I have no other PCIe cards to try. All fans and associated temps are fine as far as I can tell.
So my best guess is either I somehow fried a part of my MB causing both PCIe slots to fail, or, in the timeframe of less than a month, fried both my 770 and 460.
How can I determine what the problem is? It really sounds like a hardware problem to me if the green lines are presenting through POST. Just a coincidence that both cards fail so close to each other? Both the server and the computer are plugged into a 15A 120V surge protector (some ridiculous amount of joules), could there be a problem with feed power? Both of them have also been running at max output together before (StarCitizen on the main with random tasks on the server)
Depending on the replies I get today, I plan to partition my server's main SSD and try a fresh install of window on that with my 770 as the graphics card. If I see the problem on the fresh install, I will probably RMA the 770 (460 is long out of warranty).
There might be a few red herrings in the information above, I'm just so confused on how two cards could possibly fail in a month. Thanks for your help.