[earthboundkid]

It's pretty much the definition of false economy. Would you rather save a few cycles or suffer debilitating security bugs at random intervals? Always use calloc unless a) there's a proven performance problem and b) you know for a fact that due to careful inspection/static analysis/black magic malloc is safe. Then use calloc anyway because why risk it?

[ppoint]

It depends on the size of the chunk of allocated memory. If it is quite large, time spent zeroing it can be substantial. Then again, if you're allocating in performance critical path, you're doing it wrong anyways.