As I understand it, the number of active instruments determines the CPU useage you'll need. But from what I gather, your template size (and therefor number of libraries) is dependent on huge amounts of RAM. Right now I'm building a slave machine and wondering what the limit in terms of library size is for 128gb of ram. The chipset I'm looking at right now supports up to 256gb.
The real premium though is the hard drives, which are NVME and wouldn't be on consumer boards (HP Workstation). So if I'm limited to only a few terabytes of libaries, then it would make sense to me to shift my hardware requirements into a cheaper chipset. This chipset would only pay off if I could have say 16TB of libraries supported on it (I do not have that right now!).