I can only get 500Mbps download speed from 10G port from a NAS to the clients connected to UBNT AP, however the same client can reach 940Mbps downloading from an NAS via GbE link.
The topology is as following
Clients(Laptop A201 2x2 1.2G link speed, iPad Pro 2018, iPhone 12) <=Wifi5 or Wifi6=> UBNT U6-Pro<=GbE=> UBNT PoE switch <=GbE=> Mikrotik CRS326 <=S+RJ10 10G BaseT=> Intel X550 <=VMXNET 3=> Linux running in vSphere
I did some debugging,
1. Run iperf -r against the 10G NAS in the UBNT AP(iperf is preinstalled in Ubnt U6-Pro), it can reach the full speed of GbE, around 920Mbps
2. The same clients/AP/radio settings/ but downloading from another GbE NAS, all the clients were just right, the wifi6 clients can reach 950Mbps
3. Run iperf -r via non-mikrotik 10G link(qnap qsw-2104-2s<=DAC=> x520),all the clients were just right, the wifi6 clients can reach 950Mbps
In the end of the day, I narrowed down to the issues between UBNT U6-Pro's WLAN and CRS326&S+RJ10
I have posted a question in unifi forum and also submitted a ticket to UBNT support, but it seems it's some kind weird compatibility issue. Can anyone help on the Mikrotik side? Is there any magic parameters which I can tweak to make them work?