@ferengi CPU power must be more than enough because it has a coprocessor with aditional 4 cores for managing wifi part  from the router. So this explanation - i dont believe it. At this router , the processor does not need to compute anything that has to do with the wifi, so it must have enough power for other tasks. I have an older router - Archer C9 with weaker processor and perform better on USB 3.0 port.

@Razvan974 

I believe someone rich enough should take legal action against this trick used by tplink. Not sure you can market product with false specs. If they use universal term it should be certified. 

I get the same speeds with ax50 15MBps write and 25MBps read usb 3.1 hdd external 1 tb.

They have two routers ax50 and ax3000 difference between them being the usb port speed. Tp link fraud. 

@steve79 

I have this problem, USB 3.2 external hard drive is connected, , I'm on wifi6 5Ghz and my transfer speed is only about 15Mbps.  Does anyone know why? Is it really a real usb 3 port?  Maybe a tear down and testing is needed to find out why 

@SlowUsbPort you can have a look at the innards without invalidating your warranty here https://fcc.report/FCC-ID/TE7AX50/4295261, but as you mention further testing would be required to verify.

@SlowUsbPort 

It depends from CPU Power. ( tp-link says) Cpu is hot and low on specs and the same USB 3.0 transfer.  AX-73 for example reach almost 60mb/s on USB 3.0 port.

@steve79 

I agree. This is pure marketing fraud, just coloring the usb port to blue does not make it usb 3. Via 5ghz WiFi i am getting speeds of ~15mBps write.

Which is too low, why even bother to buy router with such high bandwidths and features if if are not able to use its full potential regretting my decision, should have trusted advice from people and gone for ASUS or netgear. Tp link using "upto" and using that term frauds

@Becoz if you are regretting your decision then ask TP-Link to refund you. When I contacted my local TP-Link representative in Greece they accepted the problem and offered to take it back for a full refund. I didn't opt for it as I wasn't planning on using the USB anyway and I am otherwise very happy with the router's performance (wanted mainly to be able to stream 4K video through wifi from my media server to home devices and this is working flawlessly) but that might be the best option for you.

I added a fan under my router today and monitored lower temps, it did not increase speed at all. That leaves slow processor, or bad/poor usb controller speed 

Its surprising that a 3core 1.5Ghz ARM7 cant deal with this much IO. The hardware should be enough, a 10yold 2 core laptop CPU can push 50-60MB/s.