Oh so actually one of the steps of our build counts the number of cpus on the machine and executes that with a parameter for a command, showing that the fast build ran with 4 cores and the slow build ran with 2 cores.
If that's the case, how come one build ran with 4 cores? It's not at all a problem for us, I'm mostly just curious now!
Wow, indeed that particular cloud running that build at that time had 4 cores configured. It's "fixed" now, thanks for the catch :)
Btw, if we figure out the way to give specific accounts VMs with more cores (sometimes the server has spare computation power) would you be interested to build on 4 cores in exchange for more pricey subscription?