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GPU odd video output issue

moocow

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Started up the PC this morning and got no video output. So I tried the following to diagnose the problem:


1. Pull the HD 7970 and plug it into my server running a 750W PSU, got video on boot and got all the way to the Windows log in screen.


2. Swap in a 520W PSU into my PC and retry the HD 7970 again, no output at boot at all.


3. Swap in a lower power 5xxx AMD card (no need for power plugs) and got video on boot.


4. Swap in a HD 5850 (need 2 6 pins) and got video on boot and can install an older driver, current using it to post on HWC.


5. Swap in the HD 7970 again to see if it's a seating issue, still no output at boot.


The only thing I'm pretty sure of is the PCI-E slot is not broken. Not sure what else to test beside swap in my server's PSU into my PC.
 

Dwayne

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Started up the PC this morning and got no video output. So I tried the following to diagnose the problem:


1. Pull the HD 7970 and plug it into my server running a 750W PSU, got video on boot and got all the way to the Windows log in screen.


2. Swap in a 520W PSU into my PC and retry the HD 7970 again, no output at boot at all.


3. Swap in a lower power 5xxx AMD card (no need for power plugs) and got video on boot.


4. Swap in a HD 5850 (need 2 6 pins) and got video on boot and can install an older driver, current using it to post on HWC.


5. Swap in the HD 7970 again to see if it's a seating issue, still no output at boot.


The only thing I'm pretty sure of is the PCI-E slot is not broken. Not sure what else to test beside swap in my server's PSU into my PC.
Odd for sure. Are you using the same cable and output connection for each test of the 7970? Are you using the same cable and input connection for the 5xxx cards? Can't think of much else different I would try without knowing the output connection and cables... ie using DP, DVI, or HDMI if you know what I am getting at.
 

moocow

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Test #1 and #5 was using a DVI output. I also tried the mini-DP and HDMI output and got nothing, very odd indeed. Using the same DVI and HDMI cables on the HD 5850 and they are working fine. The PSU are non modular so I'm stuck with the same power cables. I'm just seeking some suggestions before I tear down both the server and PC to do PSU swap.
 

moocow

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OK a quick update on my testing. Using 3 different PSU, I still get no video output from the HD 7970 in PCI-E x16. HD 5850 and 5xxx AMD would work fine in PCI-E x16. After moving the HD 7970 to the PCI-E x8 slot, I got video. Kind of weird as it worked in another board's PCI-E x16 slot. Possible motherboard issue? I'm trying to borrow a 290X to see if it would work in my PC's x16 slot to test out the motherboard fault theory.
 

Dwayne

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OK a quick update on my testing. Using 3 different PSU, I still get no video output from the HD 7970 in PCI-E x16. HD 5850 and 5xxx AMD would work fine in PCI-E x16. After moving the HD 7970 to the PCI-E x8 slot, I got video. Kind of weird as it worked in another board's PCI-E x16 slot. Possible motherboard issue? I'm trying to borrow a 290X to see if it would work in my PC's x16 slot to test out the motherboard fault theory.
Thanks for the update. I am curious to see what happens here. It seems to be pointing to the PCI-e slot, but I would have thought that the HD5xxx series cards would use the upper lanes, perhaps not I guess?
 

moocow

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Or it could be a power issue with that PCI-e slot but then why would the HD 5850 work at all since it also need additional power to drive it. Also, wouldn't additional power only come into play if you're gaming?
 

Valkyrie

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Take a real close look at your X16 slot with a magnifier. All the gold fingers should look very uniform and clean. Since your 7970 worked in another system it's probably fine, but there could be an issue with the slot. If all the contact fingers look fine you could try flushing the slot with contact cleaner.


It's also possible that a bad solder joint has progressed to open circuit which would require looking at the back of the board.
 

moocow

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Well here's an update, managed to borrow a 290X but the results aren't what I expected.


* Plugged into X16 slot, got video on boot but when I loaded up Civ 5, it crashed after a few minutes in the Reseed mod map preview. Moved down to X8 slot, same problem and the crash seem to come a bit faster. I suspect it's overheating since I'm already using a 750W PSU. Or this 750W unit is having problems.


* I recalled my first test a few days ago with my server may not be running in X16 mode because I got a RAID card in the other PCI-E slot. I probably need to retest with the RAID card removed.
 

moocow

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For those interested, here's the final update. I removed the RAID card in my server to make sure the X16 slot is running at X16 and retested both the 7970 and 290X. Using FurMark, both cards ran at least 30 minutes without problems which means there are nothing wrong with both cards. I downgraded my PC's BIOS to F9 from F10 but that didn't resolve the issue. So I conclude that it's the board that is faulty and replacing it may be a problem. A cheap Z77 on Aliexpress is still $70 USD and the supply within our own BST seem to be non existent. For now, I'll just limp along with 7970 in X8 until I get more money.
 

Valkyrie

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Well assuming you've ensured all the contact fingers are in place (and I've seen slots where they were not) you could try re-flowing the solder joints and that may solve it. If you have access to the equipment and the ability it's probably worth trying to fix it.
 

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