Gonna have to turn down the settings.
As games progress, they will constantly push the limits of outdated equipment, it makes no sense to engineer backwards. There are settings that can be reduced so that the weakest machines perform well, the eye candy is lost, but that's the tradeoff.
If you want the goodies And the performance, then you need the equipment. Options are in the game, no ones excluded, but you have to chose your level.
I'm running an AMD 2700, Radeon 9700 pro and a gig memory. I'm also running just under 3/4 on the detail pulling a constant 75/78 fps. In a heavy fight, I drop to the high 40s.
About the only time I take a hit on frames is an event where we stuff about 100 bombers with formations into a flight of fighters. That hurts, but that's also rare.
I also run Nothing at all while I fly, stripped clean. There are Many ways your system is going to react badly to frame rates that may have nothing to do with the game settings.