Why don’t you just use a supercomputer?

It’s still very difficult to get an atomic-level simulation to run on a supercomputer. These systems are extremely expensive to build and operate, and you never get the supercomputer to use for yourself; you have to share the processors with other researchers. The few supercomputers that do perform molecular simulations have been specifically designed for the purpose, and all of them are several orders of magnitude slower than Folding@home.