Some details -
I decided to upgrade my vacation home wifi from an RT-AC86U main/AP combo to an RT-AX86U Pro main/AP combo. My AC86U main/AP combo have worked flawlessly for 3 years (with the exception of the ubiquitously inaccurate client list), but the EOL announcement of the AC86U along with finding two used AX86U Pros on sale at Amazon for a really good price gave me an excuse to pull the trigger. "Used" routers on Amazon are a bit of a roll of the dice, but I did the same for my GT-AX6000 purchases, and those have been working great, so I did it for the AX86U Pros. One AX86U Pro had obviously been set up and then sent back without the original packaging, but the other looked to be unused with the antennas still in the original bags and original box. I verified that both are US country code routers.
I went with the upright form factor again because the installation locations have no room for anything else. However, the AX86U Pro, AX88U Pro, and GT-AX6000 have nearly the same hardware, and tests posted on the internet show all three models to have very similar wifi performance which is my primary need at this location.
Setup was straightforward but tedious; flash to Merlin 388, reset to factory default, and manually-duplicate router settings from the AC86U main/AP combo. Then export OVPN server config, disable Lets Encrypt, and deregister DDNS on the AC86U and set these up on the AX86U Pro. A few concerning messages showed up in the router logs as I got everything configured. A tainted process on CPU #3 showed up several times on the main router, and the AP router temporarily had an issue where a mdio phy message began showing up in the log non-stop. But after completing the configuration and installing the routers, I've not seen anything concerning in the log outputs. One thing I noticed during the setup is that the radios in the AX86U Pro take much longer to come back online than the AC86U radios when the radios are restarted or the router is restarted.
Wifi is configured to allow AX, and I manually select the channels. The 2.4 GHz band is set to 20 MHz bandwidth. The 5 GHz band is set to 80 MHz bandwidth, and the manually selected channels are not in the DFS range. This is the same config that I used for my AC86Us with the obvious exception of no AX capability, and I ran the 2.4 GHz band on my AC86Us in N-only mode. 2.4 GHz AX wifi performance is no better than my AC86U combo in 2.4 GHz N-only mode, at least at range for my Galaxy S22 Ultra. The phone loses reception at about the same range as my AC86U setup, and speeds just inside the reception limit are no better than my AC86U. Interestingly, if I set the 2.4 GHz band on the AX86U Pros to N-only, the long range performance suffers compared to AX. 5 GHz and 2.4 GHz wireless performance in the house and just outside the house are not obviously better than my AC86U main/AP combo either.
Bottom Line -
An RT-AX86U Pro main/AP combo offers no obvious performance benefits over an RT-AC86U main/AP combo for a typical internet household that gets all their data from the internet. But the RT-AC86U is EOL, so feature and security updates will cease by the end of the year. I transitioned to a Pro model to get the next gen firmware features and hopefully a long support life. If you have an AC86U that's still working, and you don't care about feature and security updates, stick with it. Its a great router.
