Not in my experince. optimized chez (optimize-level 3) where I have spent quite some time optimizing the code, is generally within 2-5x of optimized C.

I have found LuaJIT to be about that fast as well, but with quite a lot of exceptions where it is within 1.5x of C. I would say it is still the fastest dynamic language implementation.

The work done by the racket7 folks on Chez might change that though. I have been reading Gustavo Massas patches to chez, and he is a pretty bright guy :D