Multi-users bottleneck WiFi 7 6Ghz Band

[clodb]

Hello 
I have been using the BE98 router as an access point for some  experiments on 6Ghz band and 160Mhz channel (due to licensing). 
I have 24 clients which I connect to this network and a 10G backhaul to a server.

I am able to reach about 1.8-2.2 Gbps with a few clients, but the weird part is that after a certain limit, around 8 clients ( I guess because the wifi clients are 2x2, so 16 flows in total) , the aggregated traffic drops drastically, to the point that I have about 700Mbps overall uplink to the server, when all 24 devices are running iperf3 or sending data.

Does anyone know why that is ? Would I be able to do something that would change it so I can achieve better throughput ?
 
This is my 6Ghz configuration 

Thank you very much ! 

[jzchen]

Are they limited to 160 MHz because they are all 6E devices?  Or are they all WiFi 7?  Or are they mixed 6E and 7?

I'm afraid as you suspect you are reaching the limit of a single 6 GHz channel, hence why in some countries 2 are already made available...

[clodb]

Hello jzchen,  
Thank you very much for your reply. 
The devices are all WiFi 7, but I'm limiting it to 6Ghz band 160 Mhz as this is the only bandwidth that I'm allowed to operate in. 
According to Asus, the maximum throughput on 320 Mhz channel should be around 11.5 Gbps, therefore on 160 Mhz supposedly it's 5.75 Gbps, but lets say more realistically around 4.5 Gbps. I'm no where near that, even after applying certain changes, like setting OFDA and MIMO to UL only.
Atm, I'm looking at around 1.6-1.8 Gbps.

[jzchen]

I marked the two settings that appear to be 802.11ax, which may be limiting to ax throughput.  (I turned them off on my 6 GHz-2 and it shows "WiFi 7" on that specific channel).  Theoretically would be one device to the one router.

[Saltgrass]

I was wondering why you have the lowest acceptable signal level at -80 dBm.  I think the default is -70.

Your system may be wasting time trying to maintain a connection to a weak radio.