Final UPDATE:
So I caved in, and got yet another router, the
TP-Link AX7800 Triband router, just to make sure it isn't just Asus chipset and firmware that's doing somehting weird or is incompatible with my macs. It's a 350€ router here in my country and the best one available in my local store, and it's a triband with a theoretical accumulated max of 7800 vs AX86U theoretical accumulated max of 5700mbps.
So the test:
1)
First I connected the two macs to two different radios. The macbook pro to the 5Ghz radio 1 and the mac mini to the 5Ghz radio 2. These are the results:
Code:
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 75.1 MBytes 630 Mbits/sec
[ 4] 1.00-2.00 sec 62.7 MBytes 524 Mbits/sec
[ 4] 2.00-3.00 sec 21.9 MBytes 184 Mbits/sec
[ 4] 3.00-4.00 sec 26.5 MBytes 223 Mbits/sec
[ 4] 4.00-5.00 sec 87.5 MBytes 735 Mbits/sec
[ 4] 5.00-6.00 sec 91.8 MBytes 768 Mbits/sec
[ 4] 6.00-7.00 sec 88.0 MBytes 739 Mbits/sec
[ 4] 7.00-8.00 sec 93.1 MBytes 781 Mbits/sec
[ 4] 8.00-9.01 sec 86.2 MBytes 722 Mbits/sec
[ 4] 9.01-10.00 sec 89.4 MBytes 752 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-10.00 sec 722 MBytes 606 Mbits/sec sender
[ 4] 0.00-10.00 sec 722 MBytes 606 Mbits/sec receiver
Much much better, and it confirms what someone else said earlier, that I'm choking the radio when I am both sending and receiving on it, effectively halfing the bandwith. In other words 280-300 ish mbps is normal then.
2)
I then connected the two macs to the same 5GHz radio.
Code:
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 32.4 MBytes 271 Mbits/sec
[ 4] 1.00-2.00 sec 34.9 MBytes 294 Mbits/sec
[ 4] 2.00-3.00 sec 31.8 MBytes 266 Mbits/sec
[ 4] 3.00-4.00 sec 20.7 MBytes 174 Mbits/sec
[ 4] 4.00-5.00 sec 15.5 MBytes 130 Mbits/sec
[ 4] 5.00-6.00 sec 30.1 MBytes 253 Mbits/sec
[ 4] 6.00-7.00 sec 33.8 MBytes 283 Mbits/sec
[ 4] 7.00-8.00 sec 35.4 MBytes 297 Mbits/sec
[ 4] 8.00-9.00 sec 36.8 MBytes 309 Mbits/sec
[ 4] 9.00-10.00 sec 37.0 MBytes 311 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-10.00 sec 308 MBytes 259 Mbits/sec sender
[ 4] 0.00-10.00 sec 307 MBytes 257 Mbits/sec receiver
Which is in line with what my AX86U produces. Having said that, the TP-Link 7800 has a very unstable WLAN perforamnce. It kept jumping up and down like crazy. I had to run iperf3 several times before I got something that I could post. It is true what the seller said, and it reflects what this forum says and DongKnows write - TPlink is nowhere near as good as Asus. I guess you get what you pay for.
Conclusion:
300mbps when using smb over WiFi6 with just one radio is to be expected from one 5Ghz radio, it seems. At least when you live in a big city in an apartment complex with interference from neighboring WiFis (there are 40 different SSIDS in my vicinity of varying strength) with a mix of concrete and wooden walls. It's what I get testing four different routers with three different Macs and one Apple TV 4K in direct line of sight to the router: Asus AX86U, Asus AX1800U, ISPs own WiFi-router and TPLink AX95U 7800mbps. And they all produce the same results - 220-300mbps (it keeps jumping a bit - probably due to interference from surrounding WiFis and different / inferior(?) hardware.
Infuse was not affected in any way or the other, regardsless of the router running on one or two radios on the triband TPLink. Infuse produced only 60-80mbps regardless if it was the Apple TV 4K or the Macbook Pro streaming from the Mac mini.
All I can say is that Infuse is simply broken. No matter what the mods over at the Infuse-forum keeps telling themselves and its users.
As a sidenote, the TP-link produced the worst speed-test data I have seen so far in Infuse. The speed-graph kept jumping up and down like a jojo between 3mbps and 90mbps. Same in iperf3, albeit with higher speed values. The TP-link AX7800U router seems to be a very unstable router WLAN-wise, and I'm definitely returning it. It produced worse results than the AX86U. But it doesn't matter, Infuse seems to be the limiting factor. I suspect that Infuse's smb-implementation is just subpar and needs fixing.
Last but not least, I don't know how you other guys are getting 80MB/s (600+ mbps) from one wireless client to another wireless client. You must have enterprise hardware costing four figures or live in the desert far away from other people. I sure am not getting anywhere close to it and I have now tried to do so with three different macs (two of them AX, one AC), one apple tv (AX), and four different routers (all AX and one of them triband). I have factory reset the routers and clean-installed macOS, reinstalled the AX86U with merlin-firmware and even tried the official Asus-firmware, with no difference in the results. Perhaps it could be interference from neighbors' WiFi? 30MB/s (240mbps) is the best I get in a direct line of sight between the two macs and AX86U, AX1800U and AX7800U on one radio.
Thanks to everyone who chimed in to help. It has been fun and I've learned a lot. 300-ish mbps is what I'll get on my wlan, unless I get a triband, like the Asus GT-AX11000. Won't make a difference to Infuse, though... but at least file transfers between macs would be faster. But not worth upgrading from the already expensive (at the time two years ago) AX86U. I guess I'll just have to accept poor performance until we move again and I can set everything back up with ethernet again (hopefully).
Again thanks to everyone.
EDIT:
@drinkingbird I posted right after you had submitted your response. Yes, it seems like my results are what's to be expected of my consumer Asus-hardware in a very congested apartment building with concrete / woodden walls. I also have a HomePod (AC) and wifey's macbook air is AC- as well. They have good signal strength, but I guess them being AC probably affects performance of the entire network nonetheless.
As far as the streaming limits that seems to be application related.
Definitely!! But FireCore will never admit that Infuse's SMB is broken. They just give the same boiler plate response no matter what evidence I provide (copied from this thread) and others argue - "SMB is complex with lots of overhead and acts differently on wireless than it does on ethernet, you should try other protocols such as NFS or WebDAV if the smb speed does not meet your expectations or you should use wired". Ugh...
Anyways thank you.