Hmm, so you’re not really measuring link throughput, but file-transfer rate to some drive?
You’re then likely limited by CPU, especially if you’re using Samba or some other “heavy” protocol. You’ve got crypto and USB involved, both of which can be CPU intensive.
Let me clarify - my concern is that internet speeds are maxing out at 20 Mbps on wireless 5G band. What I’m demonstrating here is that the limitation is the wireless as it’s giving higher throughput over the LAN.
At last, what is your firmware version? Can you upgrade to latest 3.026 without reserving settings and try again? Download the tar file here and upload to the router’s UI->upgrade . GL.iNet download center
From my AR750S just now, link is over 802.11s with batman-adv routing to an active Linksys EA8300 (IPQ4019/QCA9888, QCA9888 for this link) in a routing situation, client over wired, then routed over 802.11s to server. ath10k (non-CT) drivers and firmware, as the -CT drivers don’t support 802.11s for the Wave 1 chip sets, from what I understand.
I’ve done that but it didn’t help. However, I did do another test. I connected to a mobile hotspot on my mobile phone and got 45 Mbps so it seems to be either the LAN interface on the AR-750S or something else on my LAN. I’ve checked my router and there’s no QOS or anything else that might be limiting so it must be the LAN interface on the 750S.
Install htop or, if already there, top, and check that you aren’t CPU-bound. Don’t open LuCI while trying to push the router hard as single-core, MIPS-based SoCs, in general, don’t have a lot of CPU power and LuCI can consume quite a bit alone.
Is your client single-stream, or does it support multiple streams? Checking
iw dev <wlan device> station dump
should show the modulation type of the connection in use.