Retina performance much worse than non-retina in Windows on Parallels and VMWare
I figured this out after a long time.

In MacOS under 'displays' I had 'More Space' selected under resolution - rather than 'Default' or 'Default for display'.

This scales the screen which works OK on MacOS and in the VM in non retina mode - but this is what drastically slows things in Retina mode. Set this to Default (it's actually faster, smoother &amp; more crisp in MacOS like that too as it's pixel perfect not scaled).