New build not posting

[Bottlenecker]

Hey there! My friend is having a bit of trouble getting his new pc to run properly.

His build consists of:
 

Ryzen 7 5800x3d
ASUS ROG Strix B550-F Gaming
32gb G.Skill trident z royal
RX 6950 XT

 

The problem he's having is that it wont even post. The debug led gets stuck at VGA. We've done the basic stuff such as resetting CMOS, updating BIOS, disabling CSM. He DOES get vga output using his old GPU (a GTX 1080). And the RX 6950 XT works fine in a different build. However, he only has a 750w PSU, could that be the culprit? I feel like it should at least post even if the PSU is insufficient.

 

Has anyone had a similar issue and found a solution? Thanks in advance.

EDIT: Only the CPU and motherboard are new parts. All the other parts worked in his previous intel based build.

EDIT 2: We got it to post after setting PCI-E to 3.0 and plugging in the monitor after powering on the pc. VGA light is still lit however, very confusing.

[Chapunna]

Try to boot with one ram stick

[Bottlenecker]

2 minutes ago, Chapunna said:

Try to boot with one ram stick

Didn't mention it in the post but we've tried this, no luck.

[Bottlenecker]

Edited with some further context.

[Chapunna]

Removed

[Chapunna]

Sorry i saw your edit now, moving gpu to pci-e 3.0 slot helped you.

[Bottlenecker]

7 minutes ago, Chapunna said:

Sorry i saw your edit now, moving gpu to pci-e 3.0 slot helped you.

We used the gtx 1080 to get in to BIOS and selecting pcie gen 3.0 instead of auto for the first pcie slot. This somehow resolved the no-vga-output issue. But the VGA light is still lit making me feel like something still isn't right..

[silencer12]

1 minute ago, Bottlenecker said:

We used the gtx 1080 to get in to BIOS and selecting pcie gen 3.0 instead of auto for the first pcie slot. This somehow resolved the no-vga-output issue. But the VGA light is still lit making me feel like something still isn't right..

Is the newer card sagging?

[Chapunna]

Just now, Bottlenecker said:

We used the gtx 1080 to get in to BIOS and selecting pcie gen 3.0 instead of auto for the first pcie slot. This somehow resolved the no-vga-output issue. But the VGA light is still lit making me feel like something still isn't right..

Okay dont worry about that, install windows/drivers do benchmarks, if everything is okay then leave it.

[Bottlenecker]

1 minute ago, silencer12 said:

Is the newer card sagging?

A tiny bit yeah, so I guess it could be losing contact with the pci-e port on the motherboard. But he's never had any issues with it in his previous build and it works now for some reason so I feel like it shouldn't be because of that.

[Chapunna]

 What happens if you move gpu to this slot?

[Chapunna]

Upper slot is 4.0 and lower slot is 3.0

[Bottlenecker]

2 minutes ago, Chapunna said:

Upper slot is 4.0 and lower slot is 3.0

We'll just leave it as it is, if it starts acting up in the future we'll try that.

[Chapunna]

1 minute ago, Bottlenecker said:

We'll just leave it as it is, if it starts acting up in the future we'll try that.

Okay i wish you best 

[Chapunna]