Hardware:
ASRock Fatal1ty AB350 Gaming-ITX/ac with P4.50 bios
AMD Ryzen 2700
EVGA GTX 950
Patriot 16GB Kit (2 X 8GB) 3400 MHz (PC4-27200) Viper 4 Series DDR4 Ram
Cooler Master 750w Bronze PSU

The GTX 950 works great in 2 other computers, one of them using the same PSU I'm trying to use in this new build. However, in the build listed above, it won't post. No beep code, nothing, other than the CPU fan spinning up. USB devices such as a thumb drive don't light up. I swapped the 950 for my wife's old EVGA 560 TI, and everything works fine, and this is the only change needed to get it running. I am positive I hooked everything up correctly, and I've tried to go through bios to see if it's an option preventing it from working with the 950 (UEFI vs Legacy support options, etc), but I am out of ideas. I turned on bios beep on POST to make sure it wasn't just a cable/output issue. With the 950 it does not beep at all, it does with the 560. I've run through many tests swapping GPUs trying to get the 950 working.

Does anyone know what the issue might be? I'm stumped.
 
 
 

bcavnaugh  PMed me (I cannot reply) and said to enable CSM and Set Video to Legacy, but I don't have that option, even after resetting my uefi settings to the defaults.

Interesting.

Update #2:
This exact same issue happens with a Gigabyte GA-AB350N-Gaming WIFI as well.  The exact same CPU and GPU combinations act in exactly the same manner, with the R7 2700 and GTX 950 not working together, but working otherwise, in other combinations of hardware.

Anyone have any ideas?

The video card is the only pcie device being used. (Only one pcie slot, and I'm not using the m.2 ATM)

I have tried changing between pcie modes with no luck. It works in auto or gen 3 mode with the a8 APU, but no mode works with the R7 2700.

It could be a voltage issue I suppose, but across 2 motherboards? I don't know what to do to fix that either.

EVERYBODY should be getting new bioses, since mobo manufactturers are now patching the SPECTRE and MELTDOWN security flaws in all processors, intel, arm, amd, everything, even cars.
If it has some sort of cpu, it is getting patched so people cant easily use the cpu to make your (whatever) their zombie machine.
;)
 
So, everyone should be getting, and using, the latest bios when they come out, or risk being taken over.
Too bad they come with speed penalties though.
:(

Yeah, some russian guy just got a ton of money from google for finding this.
But, it has been around FOREVER, and I mean FOREVER, in the instruction set. They are only going back so far (its either to X58 mobo's, or the mobo's right after the X58 mobo's came out) and only for certain cpu's.
Its like the military: Who knows what they have now, which is probably light years away from what they just exposed to the public (in the hacking scene I am talking about).
:(