Mid 2014 MacBook Pro memory specification

Retina models do not allow upgrade of RAM. Only non-Retina models have the user-addressable slots on the logic board. In fact Retina models of MBPs have a very low user-serviceable rating (ifixit.com gives a 1 out of 10 for *user*-servicable parts).

The thin-design of Retina systems require RAM soldered on the logic board and SSDs of different format than the 2.5 in drives.

Furthermore ... opening the case on a non-Retina model is a user-allowed option without voiding the warranty. Opening the case of a Retina model gives Apple the option to deny any warranty service if something breaks (logic board, display, fans, ...).

I would hardly say "stuck with". Many new non-mac systems come with maybe 8 GB, and do not manage RAM well. I have 16 GB in my 2011 MBP. When I was using it for video editing and was at 3 days into converting videos I still had 4 GB free.

Under Applications/Utilities/ActivityMonitor you can see the "memory pressure" reading of the system. Older OSXes showed numbers, newer ones tell you how "stressed" memory is. Most of the time you should see a low bulgy green bump, green and low being "good". Yellow and red telling you memory is running short.

VMs. Now it is more clear.

VMs lock the specific RAM away from general OSX allocation and almost definitely changes its allocation strategy. Recall that VM is not an optimal environment, even if running OSX in a VM. The VM shell is only as efficient as the operating algorithms which will probably not be the same as native operation.

At least you have 8 GB to allocate to both native OSX and the VM. Running only 8 GB physical requires more sacrifice.

And, if it helps, 16 GB is probably the max for many laptops these days. 32 GB in 2 SODIMMs would be both very expensive and the internal memory bus may not be able to address it all.