ok, so I installed Q4 but it has less curves than q3.
here's my config

centrino 2 ghz, 1 gb ram, nvidia go 6800 256 mb ram, 100 gb hdd.

I've tried playing on all detail levels, and I've tried every option in the q4 settings but nothing changes.
I've even tried a few drivers for the go 6800 but nothing!
here's a screenshoot. arent the ventilation oppenings suposed to be round?
and how about the tank gun? it's way to sharp imo.
will post more screenshoots if you need.

http://img402.imageshack.us/img402/5756/shot000047eo.jpg
http://img369.imageshack.us/img369/6904/shot000019kz1.jpg

It`s exactly the same on my system, I think that`s how they are supposed to look, maybe you can change them with an .ini command

its just the way curves are handled by the quake engine, and always have been for that matter (at least since curves exist)
its a mappers setting, you can have a curve with 2 sides or 20 sides. all a question of performance