Hi, I have just checked Device Manager and confirmed it with Aida Extreme, I have;
Intel USB 3.0 eXtensible Host Controller - 1.0
USBXHCI.SYS.
I am completely baffled by this as because like you, my older Fiio works fine.
As others say their X5 3rd Gen's are connecting and functioning, could mine actually be defective even though it appears to be working?
No offense, but you are taking logic shortcuts to rule out causes.
Power draw: Did you only check your port or did you check WHILE the device is plugged in? A USB port can seem fine, but it's during connection that the power draw issue would occur...
Compatibility: USB controllers can have incompatibilities due to drivers or hardware
Software: Android isn't just an OS, it's also a kernel with drivers... There's also the OS layer which is used to send the protocol used to transfer info to and from the device.
I also have an Intel USB 3 chipset which is working fine with this, so must just be a specific model...
Overall, this issue will most likely not be solved by us. Fiio has to voice in on this... I'm glad you have a workaround, but not all of us have that luxury.