Ryzen 4500 and Ryzen 5500 only support PCIe 3.0 as well.
![cpurpe91_1-1660947582639.png cpurpe91_1-1660947582639.png](/t5/image/serverpage/image-id/72211iC3879A8E4969EFFB/image-size/medium?v=v2&px=400)
![cpurpe91_2-1660947646446.png cpurpe91_2-1660947646446.png](/t5/image/serverpage/image-id/72212i0AB856CA143F8DB9/image-size/medium?v=v2&px=400)
The RX 6600 only uses PCIe 4.0 X8 so there could be performance loss if only in PCIe 3.0 mode.
The requirements I have read say you can run SAM in both PCIe 3.0 and 4.0.
Ryzen 7 7800X3D, ASUS ROG STRIX B650E-F GAMING WIFI, G.SKILL TRIDENT Z NEO 2x16GB DDR5 DRAM 6000MT/s CL30, AMD Radeon RX 7900 XTX, LIAN LI EDGE 1300, Corsair MP600 PRO NH 4TB