LAN iperf3 speed test slower than internet speedtest.net

[glens]

Yeah. It was just a quick touchpoint for the thread.

 

[Fonkin]

First, I want to thank everyone who took the time to respond and offer great insight into this issue. I wanted to wrap this up as to how I resolved the slowness issue. Amazingly it turned out to be the hardware. I went through three new 6e PCIe cards, multiple drivers, secret commands, and lots of late nights before I found one that gave me acceptable speeds. The TP-Link was the runner up (30 Mbits slower) but not as fast as the ASUS PCE-AXE59BT, which won the day for me. YMMV.

Note: Once I got the a good Wi-Fi 6e card in place, the results were nearly identical using my UDM SE router as an iperf server.

Oh, that secret command that a lot of people said worked for them:
netsh int tcp set global autotuninglevel=normal

Server: Debian Linux Box
Command run: iperf3.exe -c 192.168.5.2
Results:

Server: UDM Gateway
Results:

 

[Fonkin]

How absent minded of me, the thing that started all of this... my speed test to the internet. That improved as well, but thought you all might enjoy seeing the results.