There's not so much difference if you're writing C code, inspecting the resulting assembly, and tweaking the compiler flags and your data structures to get it t

There's not so much difference if you're writing C code, inspecting the resulting assembly, and tweaking the compiler flags and your data structures to get it to produce the assembly you want. But if you're not aware of what the compiler is emitting, it's often not hard to pull an order of magnitude improvement out of the code.