I know this is not realy on the subject but my SME 6.0B3 is running on a P1 233Mhz, 80MB Ram, 14GB HD. And it´s running with out any problem, as far as I know.
I use it as a Firewall, web, ftp and file server for my home network. So its not realy that much traffic, max 3 users at a time.
The only extra I have on it is phpBB, PHPmyAdmin and LFconnect.
So back to the question what is the minimum Hardware specs needed for SME v6?