file get contents vs readfile speed

1readfile vs file_get_contents SPEED 
2(SIMILAR IF YOU DON'T ECHO THE RESULTS)
3
41) readfile()
5will read the file directly into the output buffer
6  
72) file_get_contents() will load the file into memory, 
8ONLY if you echo the result IT WILL BE COPYING from memory to the output buffer 
9using 2 times the memory of readfile().