DaemonOfMaxwell

FYI this issue was never resolved (has stumped ASUS Level 2 tech support and they have been ignoring me/it), but seems to be some kind of Motherboard-GPU compatibility affecting power to the GPU? After extensive testing (including booting with bare minimal components, clearing CMOS, etc.) I ended up just upgrading to a new ASRock Motherboard and Ryzen 2600X processor. The same ASUS 2070 I was having trouble with my ASUS motherboard works fine on the new board.

I get positive power indicator LEDs on the graphics card, and I have already tried quite a few combinations. It seems that it is my Motherboard itself that is not delivering power?

I was able to bring the card to try it out in a different PC yesterday. It loaded up fine. It seems the problem is with my Motherboard, or perhaps the power supply, though that seems unlikely. Are there BIOS settings which could be causing a problem? Do I need something other than the default values?

It has to be a PC with enough space for the (very large) GPU card and 6+8 pin power connectors. Most computers I have access to right now are macs, laptops, cloud servers, or small form factor PCs :-(

Putting the card in another system is a very good suggestion. I think I may have a though time finding one that is suitable and can power it though...

Correct, PCI-E 6+2 PIN power cables. Not the 4+4 pin CPU cables.

I'm attempting to upgrade my computer's graphics card from an old AMD R7 to a new ASUS ROG STRIX RTX2070-08G-GAMING I just bought on New-Egg. I also had to upgrade my 13 year old 430W power supply as it doesn't have enough oomph for the new card; got a new EVGA SUPERNOVA 750W G3. My Motherboard is an ASUS ROG GENE VIII, about 2 years old. I picked the ASUS ROG STRIX partly thinking it would be the least likely to have problems with my motherboard... boy was I wrong. I switched the computer over the new power supply; no problems so far. That includes powering my old AMD R7 off a 6/8 pin connector. But when I have the new graphics card inserted my whole computer pulses on and off about once per second! GPU RGB lights flashing, all fans PULSING (case, power supply AND GPU), power supply clicking, On and off, on and off. Not enough time for an error code on the mother board or anything to show up on the monitor. Just on/off/on/off/on/off @ ~ 60bpm. I contacted ASUS and they suggested I get a replacement card from New-Egg. I received the new card today and it does the exact same thing. I've updated my BIOS, no luck, same behavior. Tried many different combinations of cables and ports on the power supply; no luck, same behavior. Tried using the other PCI Express Slot; no luck, same behavior. Tried booting with the power cables to the graphics card disconnected - SAME BEHAVIOR?!... seems to indicate a power issue... Reconnected the old power supply (only has 1 6-pin so I can't power the new 2070), tried to boot with GPU power disconnected; SAME BEHAVIOR, though my old power supply didn't click as loudly as the new EVGA one when pulsing on and off. Tried reconnecting the AMD R7 instead... still fine; I haven't fried the system. I'm at a bit of a loss here. Do I have two cards that are bad the same way in a row? Is my new power supply somehow able to power the 6-pin R7, but not the 8+6-pin STRIX? Suggestions anyone?!!