USB 3 mode

Our wifi adapter chipsets and drivers are developed by Realtek. We prefer to package their official drivers while modifying as few of the available parameters as possible. For example, Realtek has chosen to disable USB 3 port mode by default for compatibility with some older systems, which sometimes results in lower wifi connection speeds.

The instructions below mention 88x2bu, which is the driver name for our AC1L and AC3L adapters. For the AC5L adapter, please replace 88x2bu with 8821cu wherever you see it below.

To see your current speed, insert our adapter in a USB 3 slot, open a terminal and run lsusb -t. The output should be similar to this:

$ lsusb -t
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
    |__ Port 6: Dev 4, If 0, Class=Vendor Specific Class, Driver=rtl88x2bu, 5000M

If you see Driver=rtl88x2bu, 5000M it means you’re using USB 3 mode, while if you see 480M it’s in USB 2 mode. To switch from USB2 to USB3 mode, run the following commands:

sudo -i
echo "options 88x2bu rtw_switch_usb_mode=1" > /etc/modprobe.d/local.conf

Then reboot your computer and run lsusb -t again to see if the USB speed is now 5000M. Then reconnect to your wifi and check if the wifi speed has also increased.

If you ever want to undo the change, run the following command and reboot:

sudo -i
echo 2 > /sys/module/88x2bu/parameters/rtw_switch_usb_mode
rm /etc/modprobe.d/local.conf