The word is FEWER!
"The beefier your Windows Server license the less copies you'll need for running Microsoft's operating system in virtualized environments."
If they are countable, we say there are fewer of them. If it is uncountable, we say there is less of it.
"There are fewer ducks on the lake today."
"There is less water in the lake today."
It is a very simple rule. Please get it right.