It's more than that - it's all the latency that you can remove from the equation with your bare-metal server.
No network latency between nodes, less memory bandwidth latency/contention as there is in VMs, no caching architecture latency needed when you can just tell e.g. Postgres to use gigs of RAM and then let Linux's disk caching take care of the rest (and not need a separate caching architecture).
No network latency between nodes, less memory bandwidth latency/contention as there is in VMs, no caching architecture latency needed when you can just tell e.g. Postgres to use gigs of RAM and then let Linux's disk caching take care of the rest (and not need a separate caching architecture).