memcmp is also supposed to be heavily optimized for comparing arrays of bytes since, well, that is literally all that it does. msvcrt.dll is the C runtime from

memcmp is also supposed to be heavily optimized for comparing arrays of bytes since, well, that is literally all that it does. msvcrt.dll is the C runtime from VC++6 days; a modern (as in, compiled against VC++ released in the last 10 years) C app would use the universal runtime, ucrt.dll. That said, stuff like memcpy or memcmp is normally a compiler intrinsic, and the library version is there only so that you can take an pointer to it and do other such things that require an actual function.