All works fine now.
What I did :
In vmware workstation, Preferences, Memory : reducing the amount of memory to 10 gb (keeping the "Allow most virtual memory..." checked).
I think that's enough. My host pc was going to 100% memory. Now it doesn't goes beyond 95%. The VMs does swap for the remaining.
I also moved my vcsa machine to my SSD disk. If swap memory needed, it's much better on ssd.
I've tried back the vcsa on the hdd. No good.
So, to me, the vcsa absolutely needs to run on ssd. Bar none.