I don't know what level you're engine runs on, but Quake 1 was quite simple in design, but it it rran rather fast for it's level of hardware it was ment to run on.

Then again, I'm no 3D graphics expert so I cannot tell if more poligons or faces, etc will effect what, but I'm sure that a few more values for natural effect won't hurt it that much.

Then again the other imitated method could work too. What is you're hardware again?

I have a x2 AGP with 8 MB of memory(ATI MOBILITY-1 Rage). Now thats old.