Spring RTS Engine

I am running Spring on a:

Athlon XP3200+
1.25G of Ram
GeForce 6600GT

The game should run blazing fast. I have all options maxed except for Shadows, which is turned off. My framerate never goes above 40 to 50 fps. With shadows it's more like 20 to 30. On friends machines (which are worse then mine), they can get almost 150 fps with shadows off.

Anyone have any idea what mighyt be going on here?

Thanks

Shadows arn't the only thing that eats up CPU/GPU.
High Res Clouds, Dynamic clouds, Reflective water are also heavy things.
Also LOD and particles slows your game down.

I get 150 fps with one unit on my screen to 30 fps with a full scale battle (on same settings). the fps are very dynamical.

Try playing with the settings more, you'll find the perfect setting for your pc. ^.^

Almost same config (Amd64 3000+, 1 gb ram, gf 6600, running on linux) and at game start on small divide with only the commander on the screen I get 150 fps.