@steve79 

Go to the AX50 web interface on your PC (not the APP) and then go to

ADVANCED > SYSTEM TOOLS > SYSTEM PARAMETERS

uncheck USB 3.0 Interference reduction then save settings, you may have to reboot the router for it to take effect.

check if it improves your USB file transfer.

Anyone else unfortunate enough to have this router?? What USB3 speeds are you getting?. I'm only getting 20MB/S transfer. 

Worse router I've owned. Thinking of testing my new chop saw blade on it!.

@steve79 

I also get around 20MBps. I was specifically looking for USB 3.0 port while searching for the router upgrade. Is there any work around. Is it because of inadequate processing power? 

When I decided to get an Archer AX50 I also thought its USB 3.0 port would be a nice upgrade for me.

However, just like you guys I've been left disappointed.

To test the true speed of the AX50's USB 3.0 port I used an external USB 3.0 hard disk drive and connected my PC to the AX50 via Ethernet cable (1 Gbit connection) to rule out wireless as a bottleneck.

Reference data for this external HDD:
When directly connected to a USB 3.0 port of my PC it achieves >100 MBytes/s (both read and write).
When directly connected to a USB 2.0 port of my PC it averages 38 MBytes/s read and 34 MBytes/s write.

Now with the external USB 3.0 HDD connected to AX50's USB 3.0 port and my PC connected to the AX50 via Ethernet cable:
If "USB interference reduction" is enabled:   around 32 MBytes/s read and 19 MBytes/s write
If "USB interference reduction" is disabled:   around 39 MBytes/s read and 19 MBytes/s write

For the sake of completeness: Over wireless connection I only get around 20 MBytes/s read speed and up to 18 MBytes/s write speed (fluctuates a lot).
 

@steve79 It is already a SHAME for TP-LINK about USB 3.0 speed starting with Archer C9. For archer C9 is a bit faster, but much slow than the USB 3.0 specs. On this router they practically changed the USB connector and named it to USB 3.0. We all can see  that is an USB 2.0 coloured to BLUE, the colour used for USB 3.0 connectors...

@ tp-link - what do you have to say about this? You have a powerfull CPU on this router. I think you can do better on that USB 3.0 port. I think you didnt learn anything from past mistakes...

I can confirm the USB port on the AX50 is for all intents and purposes a USB 2.0 connection. I have a USB 3.0 external disk which features a two tone led, lights up blue for USB 3 and white for USB 2.0. Yup, guessed it right, it's white when connected to the AX50. The port on the AX50 is a USB 3.0 in the sense that it has the extra pins needed for USB 3, however I suspect the USB controller isn't really a USB 3 one.

TP-Link - any answer about this? Nothing? ...

I stand corrected on the supported USB type, I hadn't disabled USB 3.0 Interference reduction, as I had my AX50 in AP mode and in its infinite wisdom TP-Link has decided to hide this setting in AP mode, despite the fact that the USB share feature is fully functional in this mode.

Having said that, actual speed results are similar to what others have mentioned. Transfer speeds reading from a share through gigabit ethernet writing to an SSD were 33MB/s with reduction off and 32MB/s with reduction on. The same USB drive connected directly to the computer in question achieved 110MB/s while transferring the same 3GB file.

Had an email exchange with TP-Link support mentioning my poor experience with USB on the AX50 and they replied that their engineering department reported that USB performance on the AX50 is limited by the router's CPU power. They actually offered me a return for a full refund, so kudos to TP-Link for that, but still doesn't fix the fact that the product does not fully comply with its stated specification.