Lenovo ThinkCentre M90n

Silent operation. ; Compact and rugged chassis with no moving parts. ; Core i3 CPU can handle basic office tasks and HD video streaming. ; Plenty of ports despite tiny chassis.

Memory tops out at 4GB. ; Only possible internal expansion is storage, via an M.2 slot.

Thanks to its compact, fanless design, the Lenovo ThinkCentre M90n Nano IoT is a tiny and silent mini PC with enough power for basic office and media-streaming tasks, as well as vertical-market and digital-signage use.

Unbelievably compact chassis. ; Rugged, too. ; Competent performance. ; Plenty of ports.

Noisy during operation. ; Virtually no room for internal expansion.

The Lenovo ThinkCentre M90n Nano makes other small-form-factor PCs look enormous, but most offices would do better with a slightly larger and quieter system, leaving the Nano to serve as a streaming box or other specialized device.