NEC D720200A PCIe - Slow transfer speed

[kyriacos]

I am not sure about the firmware, but I already tried the latest drivers. But I found that others have the same problem:

Renesas uPD720200 USB 3.0 slow transfer (29MB/s) on Windows 10

Hi guys, I have a problem with 2 of the 4 rear USB 3.0 ports from my ASrock X58 Extreme6 motherboard (latest bios 1.60c). The upwards ports works perfect and have a transfer rate around 150MB/s. With the two other (underneath) I get stuck slow at around 29MB/s. The chips are Renesas/NEC uPD720200 revision 3 and are flashed with latest 3.0.3.4 firmware. I tried both Windows 10 native drivers and 2.1.39.0 (from 2012) Renesas drivers. Is there something I can do to fix this ?