Why is this gen 4 PCIe m.2 running at gen 3 speeds?

[trents]

Motherboard is ASRock B550M Pro 4. When I first got this WD Black SN770 Gen 4 SSD it was getting over 5000 mbps reads and writes but I was using a Ryzen 3700X and a discrete video card. I installed a Ryzen 5700G with built-in GPU and now am getting what looks like Gen 3 PCIe m.2 speeds. Does the APU steal PCIE lanes?

 

[EarthDog]

Does the APU steal PCIE lanes?

From the specs...

- 1 x Hyper M.2 Socket (M2_1), supports M Key type 2280 M.2 PCI Express module up to Gen4x4 (64 Gb/s) (with Vermeer, Matisse) or Gen3x4 (32 Gb/s) (with Cezanne, Renoir and Picasso)**

IIRC, that's a Cezanne-based processor, the 5700G, which is PCIe 3.0, yep!

 

[Woomack]

When I got my first 4800G, I didn't check the CPU specs and I was wondering about the same. Sadly these CPUs are limited to PCIe 3.0, but it only affects the maximum sequential bandwidth, so it shouldn't be visible during daily work.