It might have been the case for objective C in the days long gone but Xcode 8.0 does NOT make use of all the cores (at least when compiling swift).
A note to explain:
- get xcode 8.0
- run activity monitor open on CPU tab
watch the idle times during swift compile phase. THEN do be sure to downvote (once you see no significant idle).
An i7 based mac is a bonus.
UPD: It's broken in a peculiar way.
At the beginning it fires off 4-5 swift compilers to match the number of physical cores but later on it runs 1(ONE!) swift compiler
at a time leading to massive CPU underutilization.
Maybe the swift frontend can not figure out the dependencies for
a parallel build.
Note, I'm not saying: do not buy a 4 core machine! do not migrate to swift!
But activity monitor setup to update every single second
on an i5 and i7 powered macs shows only single swift compiler in flight.
It's slowly becoming a moot point as the swift potentially compiles faster than objc and there is less code to compile.
UPD20161104: note how archiving (presumably written by the old school nextstep engineers) contrasts with this newfangled opensource junk:
it utilizes just a little over 3 cores leaving 1 to have a (very) responsive system. Perfect.
Contrast that perf with uploading archive to itunes connect is at a whopping 5-7 KBps (and that is over 50Mbps fiber optic link)
I wonder where's the bottleneck on the other end.