@tonyarnold Have not noticed contention, it’s been very reliable. Note that we run this to build packages of the Swift Package Index and they have a hard build timeout after 10mins. However we really hammer this machine: each VM runs two parallel builds.
We do this, because a lot of time is spent checking out the repo and prepping the build. I.e. without scheduling 2 builds in each VM we underutilise the host.