A user in TUG reported that Tixati's seeding slows down. Further testing on their side and my own confirmed that with about 40 joined channels (pretty much all online channels today) causes significant speed drops.
The reason: Tixati is main-thread bottlenecked and if viewed in Task Manager (or Process Explorer), you can see Tixati tops out at one core load in per cent.

So it's not just the GUI that causes slowdowns.

Many people will not see the connection between many channels<>slow speed. They'll think 'I don't need to leave channels because I have a lot of spare bandwidth'

Related threads:
"Tixati EXTREMELY slow." - https://forum.tixati.com/support/3328
"New default channel directives (proposal)" could possibly help? - https://forum.tixati.com/support/7154

Unfortunately massive wins such as this are completely diminished by lack of exhaustive multi-threading

I'm the one you were talking to that day, I will say the channel directives actually seemed to help quite a bit. though I can't say for sure if this is causation vs correlation.. it is good news since the channels that were changed, changed for everyone.