Fastest practical language

I know this is subjective so there is no one answer but I would like to hear your opinions anyway.

Which language has the fastest performance for most tasks while still being practical to write in?

Extraordinary claims demand extraordinary evidence.
Stalin code claim is like claiming that in 30 years(~1980 modern C compilers), all programs have used a code path which is twenty times slower and optimizations never helped at all.
I would have believed if Stalin was writing optimized SSE4 assembly blocks, but its just plain old C code. My best guess is they use a shitty C program written in a hurry as straw-man for "hand-tuned C" and really optimized Scheme code for Stalin.