Why are M1 USB speeds slower than on Intel?

The issue is the M1 is not sending the appropriate queue command when a data packet is sent, therefore resulting in a slower performance. This affects any USB external SSD connected to an M1 Mac.

Intel Macs do not have this problem, therefore external SSDs will perform faster with Intel Macs.

The issue has been verified by chipset manufacturers, and it has been reported to Apple. So far, Apple has been silent on this problem. Hopefully a future OS update will solve it.

from what I gather, I think it has to do with Intel controller chips that Apple had incorporated into their machines along with their CPUs. since they are now "on their own" with the new Apple silicon and arm, and I think apple stopped using Intel controllers in their new hardware. I could be wrong. totally hope apple figures out how to get their hardware working up to expected par as compared to the older machines and their hardware..

just installed the Big Sur update today. sad to say, the ports are still the same. only get the full throughput on superspeed 10 devices if connected through my juiced portable hub, 10 gbps, while a superspeed 10 device still only registers in system information with only 5 gbps speeds when connected directly to the thunderbolt port.