It's great to be able to use an expressive language and to go low level and/or verbose to extract every bit of performance on hot code. I have written some amount of numerical code in C and it's not unusual to first prototype in Matlab, Python or whatever for the productivity gains and rewrite later in C (nowadays I'm using Julia and so far it's great) . That being said, the only way for language X to be faster than C is to not try very hard optimizing the C implementation.