[TikiTDO]

If your memory usage and gc speed are of critical concern, then you should really know that ruby is just not going to provide the tools you need to handle that. That's like using a hammer when you need a screwdriver. Even the most modifiable hammer is still meant for pounding, not screwing.

Whenever I see "I'll write in Ruby and optimize in C when I need to" I assume the context of "my program is well suited to be written in Ruby." For instance, I certainly wouldn't write embedded code in ruby. However, I would venture to say that these situations are the exception rather than the rule.

These days most software has access to fairly reasonable computational resources. If you're writting microcode for some industrial control system, or calculating stock price variations with micro-second resolution then certainly stick to C or ASM or what have you. However, in an age when even a fridge will have a few hundred MB of memory, and when a lot of code is meant to be just "good enough" I think even ruby will suffice.