[maxmcd]

hopefully depot will reply, but from my perspective it is mostly laid out on their homepage. they are comparing against builds in other CI products that use network-backed disks, virtualized hardware, and don’t keep a layer cache around. Depot provides fast hardware and disks and is good at making the layer cache available for subsequent builds.

You could likely get very similar performance by provisioning a single host with good hardware and simply leverage the on-host cache.