I've got a question...

Currently I'm working on a pc with these specs:
AMD Athlon 2400+
GeForce FX5200
1280 mb memory.

The terrain is counting around 102.000 triangles.
FPS is around 22.

My game is supposed to work on next gen hardware (I know, my oldie certainly isn't).
Should I tweak it a bit more (the graphics) or decrease it a bit?