There are no more server CPUs with less than 6 cores though.
We could happily manage with just 2 dedicated to SQL server, but you have to license all the cores you have. So 3K worth of low end hardware ends up costing you several multiples of that in licensing.
What features in SQL Server Enterprise do you need? More than 24 cores? More than 128GB of RAM?
I ask because SQL Server Standard is significantly cheaper when you're using CALs instead of unlimited connections. Ten servers fronting a SQL Server Standard install is $3K, which at a large enterprise is often within a director-level's discretionary equipment budget.
User CAL is only cheap if you only deal with small amount of users (internal app). Please note a user is not SQL User account, but represents actual individual person. If you have a webserver (with one db user) but a thousand of visitors, then Microsoft treats it as thousand user CALs . Following MS doc explains this in detail http://download.microsoft.com/download/6/F/8/6F84A9FE-1E5C-4... , look for keyword 'multiplexing'
Is that the case? I'm sure I've seen people running on limited cores for licencing reasons rather than having to licence every core. Not sir if that was enforced by the engine refusing to use more, or via seeing processor affinities.