Question PC doesn't POST with 7800 XT on, but does with GT740 or integrated graphics

[holasoybraianbass]

So, I've recently bought a brand new PC, no used parts, and when plugging it in I couldn't get it to POST with the GPU on. I tried a bunch of different things to get it to work, but I've had no luck. I'm going to explain in detail my situation and all the possible solutions I've tried to see if someone can narrow it down.

The problem: When I try to plug my GPU, the MOBO lights tell me it gets stuck on VGA and I get no display or POST. When I unplug my GPU everything works (and has been working for a few weeks now, since I'm writing it from exactly the same PC)

The possible solutions I've tried: - Reseating the GPU
- Using the other PCI-E port
- Connecting 2 different PCI-E Power connectors instead of the same one with multiple headers
- Using a single stick of RAM
- Updating the BIOS and GPU Drivers
- Enabling iGPU Monitoring but I don't have the option in my BIOS
- Changing the preferred display to be the external GPU in BIOS

PS: I've bought this PC in another country since the prices in my country are too expensive, so trying to refund the GPU is my last resort since I need to travel to another county to swap it for another one.
I've been wanting to test it on another MOBO/PSU but I have no one who has a powerful enough PSU that can run my 7800XT to test if it is a faulty GPU, so I have to hope it's not a faulty GPU and it's something I can solve.

Here's a list of all my components
PSU: XPG Core Reactor 750W 80 Plus Gold
GPU: Gigabyte RX 7800 XT Gaming OC 16GB
CPU: AMD Ryzen 7 7700X
MOBO: TUF GAMING B650-PLUS WIFI
RAM: Patriot Viper Venom DDR5 32GB (2 x 16GB) 7000MHz
Cooler: Deepcool AG620
Case: Thermaltake Divider 370 TG

 

[thestryker]

You've likely ruled out CPU/Motherboard with your testing so all that would be left is PSU and video card. Narrowing down which from there would require using another PSU.