PCIe Gen 4.0 Riser Compatibility with PCIe Gen 3.0 Motherboard

[stuntdude7]

This question might have been asked already, so my apologies if this is a duplicate question.

 

Will a PCIe 4.0 riser cable function with an RTX 3090 and a z390 motherboard?

 

I have a 3090, which is a gen 4.0 card, and a z390 motherboard, which only supports gen 3.0. Down the line, I'm planning on upgrading my motherboard and CPU, but probably not until the next gen AMD CPUs come out, whenever that may be. 

 

Soon though, I'm going to be buying a PCIe riser cable for vertical GPU mounting, and I am wondering if a gen 4.0 one will work in my current configuration. It would be nice to be able to use the riser in this configuration as well as in the one I will have once I upgrade the motherboard and CPU.

 

I've heard of problems with using a gen 4.0 GPU and motherboard with a gen 3.0 riser, so I am wary of mixing generations.