Not necessarily, if I allocate 8GB to a VM, my systems still runs smoothly even when I&#x27;m already using 10GB (I have 16GB). 
One problem is that the VM won&#x27;t clean up the RAM properly but the swap can handle that quite nicely actually. And I never utilize 16GB of ram, 8 would be more then enough for me and ram is really cheap these days (even on macs).