Review on 🚀 FebSmart FS-AC-Pro: High-Speed PCIE USB 3.1 Gen 2 Card with USB-A & USB-C Ports for Windows/Mac OS - Self-Powered Technology Included! by Dave Baker

I connected an external M.2 SSD to this card. First I connected the drive via the USB-A port by launching Disk Mark. You can see I got over 1000Mbps sequential read and over 900Mbps sequential write. When I plugged them into the USB-C port, they dropped to 44 Mbps and 43 Mbps, respectively. I repeated the same test with the Samsung T5 external hard drive and got 565 Mbps reading and 531 Mbps recording via USB-A to a USB-C port. They dropped to 44 Mbt/s and 40 MB/s, respectively. Low speeds correspond to USB 2.0 speeds. Update: I am changing my rating to 5 stars. Upon further investigation, I found that it wasn't a USB-C connector, but rather lower cables. When I used the USB-C to USB-C cable that came with the card, I got the same speed as the USB-A port. Extracted lessons, use good cables.