SEP GUP Server Specification

Hello all , I need to set up a GUP server that will facilate around 600-700 endpoints to server them definations. Please tell me what should be the specifcations i.e Hardware/Software for this server. This new GUP server machine will be dedicated only for the GUP server no other application/task will be done on this server. Please tell me the following points keeping into consideration that it iwll server 600-700 endpoints.

1. What should be the Operating system
2. How much RAM of this server
3. How much processor
4. How much Hard Disk

Regards