Deployment- or infrastructure diagrams support overall understanding of the underlying hardware.

In addition to this overview it is useful to understand the reasoning behind the hardware decisions, the selection of specific machines, processors or other devices.

If hardware plays an important role in the architecture, you can even use a node-template for that purpose, similar to the following table:

Node <node-name>

Responsibility what is the role of this hardware element, what’s it doing?
(technical) characteristics i.e. nr of cpus/cores, memory, throughput, nr-of-ports, vendor, model…
associated building blocks   what part of the software is running on this hardware?
reason for selection why was this particular hardware selected?