Recently put together what was supposed to be my dream PC: Ryzen 9 5900x, 64g of Gskill trident neo RAM, Samsung 980 pro 2tb on an X570 Aorus master MB, Corsair HX1200i PSU and the cherry on top an RTX 3090 FTW3. Am using an LG CX55 OLED for a monitor with an HDMI 2.1 certified cable. On first power up it looks like it's starting to boot I see the Aorus logo with a spinning wheel and then it goes black and the tv displays the "no signal" warning. I wait while the motherboard cycles through a number of debug codes but never posts. VGA LED stays lit on mother board. After several manual restarts I finally got to bios, installed windows and was able to complete set up but when I restarted for the updates I got the same "no signal" deal with the VGA light on.
 
This happens every time on cold start and restart when using the HDMI port. If I use one of the display ports to plug into my 1440p monitor the system boots normally. I have another system with a Gigabyte RTX 3080 Vision OC which runs perfectly on the LG using the same cable so I'm pretty sure it's not an issue with the cable or TV. I would hate to think I got a bad card from EVGA especially considering how hard it was to come by but I'm starting to lean that direction. I bought this card to push the limits of my 4k 120hz tv so it's not much good to me if I can only use it on display port monitors.
 
What I've tried: Remove and re-seat GPU-no change. Removed custom power cables and tried the ones that came with PSU-no change. Tried every HDMI cable in the house and every input on the TV-no change. Swapped out EVGA 3090 for Gigabyte 3080, system boots normally with 3080 installed so it pretty much has to be a problem with the 3090 FTW right?
 
Looking for advice from anyone with the same or similar issues before I try to RMA.

arestavo
Turn off - it's been the fix for many, many, many people trying to get HDMI out of the 30 series (especially for those with LG CXs)

Thank you for your reply @arestavo. I forgot to mention in my opening post that I also tried changing some settings in windows and bios including turning off fast start in windows and quick boot in bios but it did not resolve the issue.

Sajin
Bios completely up to date?

Thank you for your reply.

Yes bios and nvidia drivers are latest versions. I have also tried flashing older versions with no success.

@arestavo I agree definitely a weird situation. I have indeed seen many users say they fixed this by turning off fast start up. Others have had success with different cables or flashing an earlier bios but so far none of these has worked for me.

I will definitely contact evga support and I want to do a bit more troubleshooting on my end this weekend when I have the time as well.

Thank you for your help. I will update as soon as I have something to report.

Does the HDMI output give a signal to your monitor, After Win10 start/log screen appears ?
 
I have some PCs that HDMI does not output a signal "no signal message on monitor" until Win10 finished loading
 
New builds before drivers are installed & setup -or- while Win10 is updating - loosing signal on several PCs I've worked on

I decided to try one more thing before requesting an RMA I put the EVGA 3090 into my other system, the one I swapped the 3080 from and it boots fine. So now I'm really confused. Both systems have the same mother board on the same bios so idk what to think. I'm back to considering other possibilities gonna try a fresh install of windows because why not at this point.

Found this thread googling my issue. Same video card.

I just thought i fried my video card.
I had 2 display connected, one old tv (off), and my main monitor via display port.
I plugged in another monitor through display port, and got no video on both monitors.
Replug, no video. Restart, no video. No output from any DP port. Unplug all, turn off machine, power switch off, power switch on, turn on, turn off, power swithc off, plug in primary monitor via displayport, no video.
I'm a little upset at this point. Maybe it's just the DP that died?
Turn off pc, unplug everything, Plug in HDMI tv, get video out through hdmi
 
Restart into windows with just HDMI, plug in a DP port in windows, get picture again. All monitors now work, unplug hdmi still works, everything back to normal.

Can an engineer chime in **** is happening here? Sounds similar to issue op was having.

Hyperion_365
Recently put together what was supposed to be my dream PC: Ryzen 9 5900x, 64g of Gskill trident neo RAM, Samsung 980 pro 2tb on an X570 Aorus master MB, Corsair HX1200i PSU and the cherry on top an RTX 3090 FTW3. Am using an LG CX55 OLED for a monitor with an HDMI 2.1 certified cable. On first power up it looks like it's starting to boot I see the Aorus logo with a spinning wheel and then it goes black and the tv displays the "no signal" warning. I wait while the motherboard cycles through a number of debug codes but never posts. VGA LED stays lit on mother board. After several manual restarts I finally got to bios, installed windows and was able to complete set up but when I restarted for the updates I got the same "no signal" deal with the VGA light on.
 
This happens every time on cold start and restart when using the HDMI port. If I use one of the display ports to plug into my 1440p monitor the system boots normally. I have another system with a Gigabyte RTX 3080 Vision OC which runs perfectly on the LG using the same cable so I'm pretty sure it's not an issue with the cable or TV. I would hate to think I got a bad card from EVGA especially considering how hard it was to come by but I'm starting to lean that direction. I bought this card to push the limits of my 4k 120hz tv so it's not much good to me if I can only use it on display port monitors.
 
What I've tried: Remove and re-seat GPU-no change. Removed custom power cables and tried the ones that came with PSU-no change. Tried every HDMI cable in the house and every input on the TV-no change. Swapped out EVGA 3090 for Gigabyte 3080, system boots normally with 3080 installed so it pretty much has to be a problem with the 3090 FTW right?
 
Looking for advice from anyone with the same or similar issues before I try to RMA.

I had  a similar issue with 2080 super where hdmi port wouldnt work but DP would.  Mine looked like it was a driver problem , bcos HDMI port worked when I had a clean instance of windows.  But after installation of nvidia drivers it started playing truant again, I stopped using HDMI port altogether.

Hello! I was having the same problem and after trying literally every suggestion I could find I found something that worked. In Bios, I disabled PEG0 ASPM, from what I understand this essentially puts unused outputs into a sleep mode, after disabling the HDMI port I was using as a second "monitor" to my TV came on no problem. Hope that helps! 
 
 
No, no, nevermind, I forgot that I'd plugged the HDMI into the motherboard, it did not fix it. Sorry for my hastiness.