Just wanted to add, don't stop at the recommendations the software suggest.
I had a client who decided to go with the hardware recommendations provided by the software vendor against my objections. Six months after we were up and running, the software which was the entire point of the ordeal released an update that slowed everything down enormously. Turns out, their "recommended" hardware specs were slightly better than their minimum specs on the new version of the software and the server had also been purposed to do a few other minor things that ran in conjunction with the software. You might as well say it was the minimum.
So by stopping at the recommendations of the software vendor, they were presented with a setback no one was really thinking about. They could either roll back the software version negating the support and upgrade purchase plan, suffer the slow speeds and hope the vendor doesn't slow it any more, or replace good hardware that they really didn't have a use for outside of the specific software. They eventually let me completely overkill a server to replace it.
So unless the software vendor says there is a limit, reasonably increase the power and memory of their recommendations for future proofing. Just keep in mind you will want to eventually replace the hardware anyways else risk suffering down time from the inevitable failures.