Stefan Mileschin

BIOSTAR introduced the A620MH Aurora, a Socket AM5 Micro-ATX motherboard based on the AMD A620A chipset. In case you're wondering, the A620A is a revision of the A620 that's based on the same physical chip as the ASMedia Promontory driving AMD B550 chipset, according to this user on the AnandTech forums. First party documentation from AMD is sparse. The A620 (without the "A" suffix) is based on the newer Promontory 21 silicon, and is essentially a B650 with a few features disabled. The A620A, on the other hand, is practically a B550 on the Socket AM5 platform. Why this matters is that the chipset bus for the A620A (aka B550) is PCI-Express 3.0 x4; whereas the A620 uses PCI-Express 4.0 x4. The A620A appears to have the same downstream connectivity as the A620, and since even the A620 has PCIe Gen 3 for its chipset-attached M.2 NVMe slot(s), for the most part the performance difference will be negligible, unless there are other bandwidth-hungry devices connected to the chipset. On both the A620 and A620A, motherboard designers are allowed to wire out one CPU-attached M.2 NVMe slot capped at PCI-Express 4.0 x4.

https://www.techpowerup.com/319796/b...-a620a-chipset