2 Answers
The following are the RAM requirements defined for Windows Server 2008 and Windows Server 2008 R2 by Microsoft:
Minimum: 512 MB (You may face slowness on server)
Recommended: 2 GB or more. (Server will run smoothly)

The following are the RAM requirements defined for Windows Server 2008 and Windows Server 2008 R2 by Microsoft:
Minimum: 512 MB (You may face slowness on server)
Recommended: 2 GB or more. (Server will run smoothly)