For some reason, every time I try to go on multiplayer, it is so slow it's unplayable. Does anyone know why? Thx

Do you have shaders on?
Also when you play toribash, try exiting out of other windows and see if that helps.
You can also try frame skipping, too.

Shaders are on, its the only application open, and single player works fine.

Is it any mod in particular that's slowing down?

Is this your first time on multiplayer? Also try it w/o the shaders on.
Also see if your computer is trying to block online access for toribash.
(a firewall maybe)

If you have shaders on that might be a problem, try turning of some of the shader settings until it can handle it well enough in Multiplayer

k, thx. Another problem is that the rooms are taking an extremely long time to come up.

It might also be that you have a slow connection?
Do you use Dial Up?