I'm also curious to learn where was the bottleneck in both tests.
I've read stuff about how the M1-packing MacBook Air shipped with a SSD whose burst write speed was far higher than the one shipped in older MacBooks. The bottleneck on build jobs tends to lie on disk access, specially with projects comprised of a significant number of small files whose build also outputs a bunch of small files.
This is one of the reasons behind doing builds on RAM drives.
If that's the case then these weird speedups might not be due to magic properties on Apple's M1 professor but due to the fact that the processor doesn't idle as much while waiting for all those reads and writes to finish.
Sequential performance is only one facet of overall SSD performance. Some older Apple SSDs weren't the greatest at random reads and writes - it's possible these new ones are quite a bit faster in that department, FWIW.
I've read stuff about how the M1-packing MacBook Air shipped with a SSD whose burst write speed was far higher than the one shipped in older MacBooks. The bottleneck on build jobs tends to lie on disk access, specially with projects comprised of a significant number of small files whose build also outputs a bunch of small files.
This is one of the reasons behind doing builds on RAM drives.
If that's the case then these weird speedups might not be due to magic properties on Apple's M1 professor but due to the fact that the processor doesn't idle as much while waiting for all those reads and writes to finish.
If anyone has any data on this, please do share.