Not really a problem, but a bit frustrating. You may (or may not) have noticed my post about sticking a new wifi 6 card in my laptop. Straight off it worked fine, but when I let Windows do its latest feature update, it added a new driver, and the performance dropped back to 802.11 AC. 

A bit of checking showed that what was actually happening, was that the card is not connecting to the wifi 6 router/hotspot at all, but instead to an 802.11 AC hotspot upstairs, even though that produces a weaker signal. What's more, with the upstairs hotspot (an AC1900 device) turned off, the card prefers the wifi signal from the router next door, even though that's much weaker, and an AC1200 device. 

The ISP's router, my wifi 6 router set as a hotspot, and the hotspot upstairs all have the same ssid, so I enabled the guest network on the wifi 6 router and gave it another ssid. When I specified this, the laptop connected fine and we were back to wifi 6 download speeds, so it can actually use the wifi 6 router, it just doesn't choose it when faced with 3 devices using the same ssid, even though it's easily the strongest (I used WiFiAnalyzer to check and there's quite a difference.). 

Back to the old driver and it works fine.

At the moment it's not a big deal, but swapping back to the old driver can be PITA, particularly after a Windows update when you can't just "roll back", and I can't avoid updating forever. 

Any ideas where I can start?

Well, did another little experiment. Turned off the upstairs access point. I can't turn off the router next door because it's where the fibre comes into the house (and I can't be bothered to re-route everything) so I changed the ssid it uses. That means that my laptop can only use the router in the sitting room.

Yes, it connects fine.

In addition, before I changed the ssid on the router next door, I put some kitchen foil between it and my laptop (tinfoil hats work!) which reduced its signal strength to -89dBm, which is less than our neighbours wifi and my effing laptop STILL preferred it to the -35dBm router sitting 2 metres away.

weirdest. issue. ever.

 

>3 devices using the same ssid

?

3 devices.

1 is the router from the ISP
2 is the TP Link WiFi 6 router in AP mode
3 is the TP Link extender/Access Point in AP mode

What's the issue? 

I did not know multiple devices could/should share the same ssid.

they can if they're a mesh network... but I'm not sure that's what this is.

The bit that seems odd to me is having the router from ISP being any more than a modem, I think. I have my IPS (cable) thing being in modem-only mode so that my mesh router can handle all the rest of it. But I don't like messing with network things so yeah, got a mesh setup and don't often have to think about it.

Access points can have the same ssid, both mesh and non-mesh. That's the way our home system has been for the last 5 years or so. Mesh systems do several things which are an advantage over non-mesh systems, such as getting rid of any "stickiness" during roaming, so that your phone, for instance, doesn't hang on relentlessly as one AP gets weaker and weaker, refusing to reconnect to a nearer one. Wifi coverage can be wider and stronger as well. You can achieve the same with a properly configured non-mesh system which has a network controller included, but I haven't got the time or patience for all that malarky, and anyway, if your APs are in the right place and strong enough (and are wired APs rather than repeaters), there's precious little difference in an average house.

Until this happened to me :(

Even now it's not a big deal, just annoying.

 

not a big deal but annoying are the most annoying kind! You know that every minute spent on it is basically a waste of time but also they just won't let go, nagging annoying pests.

Just that.

Been looking through the intel support forums. Nothing similar yet, but a shit-ton of problems with the last two driver releases. 

Annoying I can live with. The most annoying kind aren't *merely* annoying, they strike terror of data loss, system reinstall, and $$$ hardware replacement.  :-@  :'C . Sometimes you get an upgrade out of it, but lord what pain.