2020 MacBook Air 1 port is half the speed of the other

2020 MacBook Air Big Sur USBC/Thunderbolt ports. The port to the back, closest to the hinge is about 1/2 the speed of the front port. I used Black Magic DiskSpeedTest on two newer SSD’s. They get over 850MB/s on the front port but only up to about 480MB/s on the back port. Used different cables and different SSD’s (Samsung T7 and Sandisk Extreme). Same general results.

Is there a software fix or other verification? I can live with this, but prefer the MB to work as it should.

Many thanks

Tom