I’m not sure about this but is there a way you can make it to where ragdolls aren’t so stretchy?!
Dynamics simulation of stiff jointed systems requires more cpu time to be devoted to the simulation. There are several ways of improving it. You could start by playing with the frame rate of your simulation, or the physics engine Substeps.
I must be misunderstanding something about your meaning, because it doesn’t sound right at all. Why would rigid physics, whose calculations boil down to wholesale location/rotation operations, be slower that Soft Body, whose every vertex needs to be processed according to the tension on its edges?
For example, in the BGE the Soft Body type is the most expensive type, much more than Rigid Body or Dynamic.
In the regular (non-BGE) animation simulator, as far as I know Rigid Body configurations are not even possible (so no direct comparison can be made in this toolset). I would like to be proven very wrong on this, though.
Back to the original poster’s question, how is this ragdoll set up? Is it individual objects linked with Rigid Body Joints? Something else entirely?
I can see why it seems counter-intuitive. Without getting into the maths of it, the best way to think about it is that to simulate a ‘stiff’ system, you need to be able to deal with rapid changes in the state of a system and to calculate them more accurately than you would in a more forgiving spongy system, where you are less likely to notice errors in the calculations.