No output from GPU in PCI-E slot

[sleepingfish]

Setup:

CPU: Intel - Core i5-6500 3.2GHz Quad-Core Processor
Motherboard: Asus - H110M-A Micro ATX LGA1151 Motherboard
Memory: Crucial - 8GB (1 x 8GB) DDR4-2133 Memory
Storage: PNY - CS1311 120GB 2.5" Solid State Drive
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive
Video Card: Gigabyte - GeForce GTX 970 4GB WINDFORCE 3X Video Card
Case: Fractal Design - Core 2300 ATX Mid Tower Case
Power Supply: EVGA - 500W 80+ Bronze Certified ATX Power Supply

Problem:

The GPU outputs no signal (HDMI) to the monitor, but otherwise seems to be working fine. I can connect the monitor to the motherboard and use the integrated graphics, and from there I can get a display. While attempting to display through the GPU, I can remote in and view my desktop just fine, despite it not showing up on my monitor. Strangest part is that the PC recognizes the GPU in device manager and indicates that "this device is working properly."

Some context:

I've had the PC for about a year and have had no other issues. This happened about two months ago. I attempted to switch the HDMI cable from the monitor I was using to a TV, and found it didn't work. Plugging it back into the monitor still didn't work. After some initial troubleshooting I gave up, convinced that the CPU was fried (had some temperature alarms in the preceding months, found the HSF loosely attached to the CPU, and was never able to get the display coming through the integrated graphics as I am now) and that I'd have to buy a new one. I finally bit the bullet and got a new CPU only to find the issue unresolved.

Fixes I've tried:

Taking everything apart, putting it back together. Reassembling everything outside of the case (this is where I first got a display from the integrated graphics). Resetting CMOS. Changing primary GPU to PCI-E in BIOS. Blowing dust out of the PCI-E slot. Washing the dust off my GPU in the sink (not really).

Only thing I haven't tried is swapping out hardware, i.e. using the GPU or mobo in a different setup to see which might be having issues.

At this point I'm pretty convinced it's the PCI-E slot and that I need a new mobo. The weight of the GPU puts a fair bit of stress on the slot, and when reassembling everything it felt a little wobbly even when fully inserted.

However, I can't look past the fact that the PC seems to recognize the GPU. When viewing my desktop remotely while attempting to display through the GPU, I could uninstall/reinstall graphics drivers and open the nvidia control panel. I could NOT select "preferred graphics card" in the nvidia control panel, though. I remember that being an option before. Also, not sure if this is relevant, in devices manager my monitor shows up as "Generic PnP monitor," but under "audio" shows "Acer ###." Don't know what that's typically supposed to be. Drivers are updated.

I'm pretty close to snagging a new mobo, but I'm not certain that it's not a GPU issue, or even something else (PSU?). I'd hate to throw more money down the drain. Maybe I'm doing something completely moronic and it's not a hardware issue at all. That'd be sweet.

Is it possible that my PCI-E slot is only partially functional? Maybe it's only broken enough that it won't output a display, but not broken enough to fail to recognize the GPU.

I'm stumped. Any help is much appreciated!

 

[DRagor]

If GPU works (and all you described makes me believe so), the simplest and most likely answer would be failed HDMI port on GPU. So please check first other output ports on GPU.