Like i said, i have not done this in a while and maybe the issue was with me and a much older machine. Expand my horizons please.
I got into VMWare and VirtualBox as ways of keeping in touch with some older systems so I could still get all historical with early skinning...ie Litestep, etc.
When I did I had probably at the time the most powerful non-server class PC money could buy....[though it cost a lot of money - Over 10K AUD]. It was back when a GTX 980 ruled the roost...and M.2 drives had just been released...along with DDR4. This was at a time when the system [Win 7] had to be coerced into booting into a M.2 as both that and DDR4 wasn't yet recognized by MS's current OS.
So when the average machine thought they were good with 8 GIG of DDR3 I was running 32 GIG of 4 in 2 slots in a MoBo that could handle 4.
All that said, I often had several VMs running at the same time, apportioning as much ram as I liked. The only downside [mostly] was with VM graphics acceleration....though that has improved over the years.
I did this machine about the same time Frogboy did something virtually identical...but since then he's had a few more systems...and I'm still on the same one....only difference is the GPU is updated now on mine.
Bottom line is....other than gaming, a modern VM on a good system is actually superior to what was available when you used to run that OS on contemporary hardware. [who needs a Pentium anyway]...
I also have an emulator somewhere for the Csirac Computer [the only complete first generation computer in existence] tho it doesn't do a lot...