Someone wants to setup a new ZCM 10.3 server
Using embedded database

Eventually may have 3,500 workstations.

Does it matter which OS in terms of performance?

(My opinion is that the SLES box will be a bit more efficient than Windows but not sure by how much).

4GB RAM, dual core CPU, lots of disk space.

No patch management
Most bundles are already stored on a separate network "share" (for lack of a better term), so not a lot of content in the actual repo on the server.
Remote Control
Imaging (not sure if they'll be using the external images on a separate share or embed them into the content repo)