ET problems \o/

Today installed ET (yay!) to run around pubs and shizzle, but it's impossible to do that - game all the time is constantly freezing for 0.5sec every 3-4 seconds. Tried to set game process priority to High and Realtime, but that ofcourse doesn't help. In background there's running only chat, so computer isn't loaded with useless processes.

Also tried with very default config, with my own config and still the same problem ...

Any ideas what could cause such "lagging"?

Running it on FaildowsXP SP2
Installation - etui 1.5
PC specs - at profile.

Halp!