I'd love to see sketchy physics to take advantage of CUDA and the nvidia graphics card. I bet it would have to slow down the frame rate so you could watch it. 😛

This is a quick summary of the results so far (all with hardware acceleration turned on). Thanks all 😄

Operating System, CPU @ GHz, Cores, Graphics card, Shadows ON / Shadows OFF

WIndows 7 32 bit, AMD Athlon II X4 620 @ 2.60 GHz, 4 core, ATI Radeon HD 4200, 8 fps / 19 fps
Windows 7 32 bit, Intel Core duo E7500 @ 2.93 Ghz, 4 core, Nvidea QuadroFX 380 LP, 22 fps / 34 fps
Windows 7 64 bit, Intel Core i5-2500K @ 3.30 Ghz, 2 core, Radeon HD 6800 Series , 15 fps / 57 fps

So far, all the listed cards benefit (in the region of an order of magnitude faster) from having OpenGL hardware acceleration enabled.

hmm, i totally would have just used a bunch of motors and set the max speed somehow to a ratio... like, 1:2 gears, motors turn .5:1, controlled by same slider.

Just in case anyone is interested, I have attached a model using my magnetic clutch idea I mentioned earlier, combined with the helpful ruby control codes from Mr K, which allows the driven part to free-wheel when the clutch is disengaged. By changing the status of the yellow driven part in the model to "static", the clutch becomes a dynamic brake powerful enough to stop the motor. Might be an idea to have a clutch/brake joint in SP 4.0?

magclutchK.skp