Thank you for the quick response Wila. This particular case is using Workstation Pro to manage VM(s) to run the automation system in a small pharma production facility. As your reply suggests, the real answer is "It depends"

I didn't write a lot of detail in the post. I originally did add details that would give a better picture to facilitate the most accurate description of the conditions, however the Website froze on my side and....z-z-z-z-zip, there it went..

This is one of those systems that runs within a "framework" so there are probably 40-50 apps and services running all   the   time. Current at rest (no human touch or manual interactions) CPU load is around 40% with some pretty regular (multiple occurrences per minute) spikes and drop offs. There is one Database Historian running, scanning the control system for around 250 measurements per second and writing to disk archiving those measurements. It is a proprietary database (OSI PI) and is incredibly efficient, but still...

Additionally there are thousands of pieces of data, most in sub second time frames traveling in all sorts of directions between the various applications. There is a small SQL database, but it is pretty static and is mostly a depository for settings, equipment parameters and descriptions. Sadly, this is a production system I am trying commission and is behind schedule. Little to no time available for good testing regimens. 

I am suspecting the current single VM is having a little intermittent trouble keeping up the pace. It is currently getting assigned 50% of the 32 GB host memory and I think maybe 5 cores of a 10 core CPU. A single 1TB 7.5K spinning drive is split 50/50 between host and VM. 

Does this sound like I would get any oomph by giving the VM more of the host resources? That feel like the direction I should go rather than add overhead with 1-4 additional VMs. I've considered moving to SSDs but I don't think there is much for the buck there.

Does anything in this additional information make you sway confidently in one direction or another. It's the client's machine so I don't have much pull in getting more horse power there. I prefer isolation as much as possible too. In this case I don't want to do that if it will cost me performance on an already borderline VM system.

I welcome your thoughts