Any slowdown wouldn’t be due to CPU speed, but to disk speed.
To compute the checksum you have to read the entire executable, but to execute it, you only have to map the parts that are needed at startup into memory.
That, I think, is the reason Apple didn’t do this at every process launch before: their OS supported (too many) systems that booted from a spinning disk.
To compute the checksum you have to read the entire executable, but to execute it, you only have to map the parts that are needed at startup into memory.
That, I think, is the reason Apple didn’t do this at every process launch before: their OS supported (too many) systems that booted from a spinning disk.