All this theoretical bottleneck debate, but it really boils down to this:
If you're writing frequently-run code in Python/Ruby/JS, or any such highly-dynamic-at-runtime language, then chances are very good that your CPU, memory access, CPU cache, etc are going to be part of your bottleneck.
Write in something that doesn't effectively turn an i7 into a Pentium 4 (and be sure to use efficient memory management techniques), and your chances of main bottlenecks being IO-only are much better.
The belief that IO is the only bottleneck is a self-defeating prophecy. It leads to code and techniques that cause CPU to become a bottleneck once again. Don't forget Wirth's Law.
If you're writing frequently-run code in Python/Ruby/JS, or any such highly-dynamic-at-runtime language, then chances are very good that your CPU, memory access, CPU cache, etc are going to be part of your bottleneck.
Write in something that doesn't effectively turn an i7 into a Pentium 4 (and be sure to use efficient memory management techniques), and your chances of main bottlenecks being IO-only are much better.
The belief that IO is the only bottleneck is a self-defeating prophecy. It leads to code and techniques that cause CPU to become a bottleneck once again. Don't forget Wirth's Law.