PCIe-4 riser cable compatible with PCIe-3 Slot?

[Brownz]

I recently purchased a SSUPD Meshlicious Case with PCIe-4 riser cable. Thing is I tried plugging in my PCIe-3 card and PCIe-3 motherboard and got black screen. Used my old PCIe-3 riser from Loque Ghost S1 and works fine. I know I dont need a PCIe-4 cable with my hardware, but I do plan buying the next Ryzen Zen 4's next year and a PCIe-4 GPU soon.

I know a lot of people say that PCIe-4 is cross compatible with PCIe-3.
Should this setup be working, or is the riser cable broken?

 

[StarShock]

Riser cables can cause all sorts of weirdness. It could very well be that it just doesn't like your specific motherboard or the way its set up in the bios. could try to set the PCIE to gen 3 in the bios rather than auto and try it again.

 

[EsaT]

PCIe v4 has lot tighter signal quality requirements than PCIe v3, so it should definitely work at lower speed.
But because of those very hard requirements needing signal "amplifiers"/re-timers after certain trace lenght there really aren't PCIe v4 risers on consumer market.
That rises question of validity of that cable in the first place.

 

[sy-core]

I'm sure there's an option in the bios that let's you change what gen pci-e works at. It may just be that you need to change this. Or again it could be a bad connection. Saying that I just bought a riser cable x4 and pretty sure it's only plugged into x3 slot. Strangest thing happened to me is games minimise and I have to use task manager to bring them to the front again.

 

[Brownz]

Thank you all. I should have thought to check the bios. Changing it from auto to PCIe-3 has solved the issue.