Frame skipping doesn't really help too much.
If you are having poor performance running Toribash without shaders,
There's not really much that you can do graphically that will help you.
You see, Toribash without shaders is not graphically intensive at all.
The processing power it uses goes more to the physics calculations, to determine what happens to your body when you alter your joints or contact the opponent or ground (or environment).
This explains why if you and your bout partner are balled up in a grabfest, your FPS will drop significantly because there are so many collisions and related calculations.