Hey ,
i had that fps problem with ET, just pust add
/r_primitives 2 in console or seta ... @ cfg.
And for ATI/AMD graph cards , my mate Kanye told me to add add atioglxx.dll in etmain.
and then managed to play at stable 125 fps .
(many of you may already know about that , but thats my first AMD card so.. i had no clue)
Unfortunately the link he gave me is no longer working, but just google it and you will find many conversations about it .
I just uploaded the one i've in my etmain folder in case you wanna try it :
http://a4fqfwb9gv.1fichier.com/