You have a AGP card? I bet you will get a hell of a lot better fps with a PCI-Express card! Also, turning down AA from 4X to 2X also really helps. I have also turned vertical sync off to get higher max fps. Also try water=0. You are flying, not bathing!
. Yeah I know, eyecandy is eyecandy, but when you have an old stoneage pc like mine you ditch some eye candy!
BTW: I have also read some settings to change in conf.ini if you have dualcore? Something about "ProcessAffinityMask=1". I may think you have it right but can´t remember!