Will switching from PCIe 4.0 to 3.0 in BIOS degrade performance?

[Youda008]

I have a Ryzen 3700X and Radeon 5700 XT mounted on Asus TUF Gaming x570.

Recently i bought a VR headset HP Reverb G2, but i'm unable to make it run properly, having constant audio dropouts with right speaker not playing at all.

I found some advices on reddit to switch all PCIe lanes from 4.0 to 3.0 in my motherboard's BIOS, but i'm affraid that it will degrade the performance of my GPU or SSD.

How much difference is there between PCIe 3.0 and 4.0? Will it make noticable impact with this GPU and motherboard?

[Hewie]

Most GPU's arent using that much bandwidth yet, it will become more of an issue if you want to use direct storage down the line but as far as I'm aware you should be fine for now.
Good news is you can always switch back later if it's a problem! 

[Haro]

Considering the 5700XT doesn't come near to saturating X16 PCIE 3.0, let alone 4.0, you should be fine in that regard. 

As for your SSD, assuming it is actually a 4.0 drive (because otherwise it wont even run at that), I highly doubt you read and write a lot to the point of saturating PCIE 4.0 bandwidth; an average user's workload certainly doesn't come close to being limited by X4 PCIE 3.0. You shouldn't see any performance downgrades when switching to 3.0.