I’d invite you to the dark side, Bapster, but you can get a feel at VI Control if you’re so inclined
Rest assured, Sampletank and most of NI or OTS don’t need heavy lifting.
But if you’re thinking of the larger orchestral libs from East West, Spitfire Audio, Orchestral Tools, VSL and the like, well …
That PC of yours should run them easily if your cpu is up to date, your Mac Pro may be up for an upgrade though. Those internal drives may also run a bit slow. Or not