I replaced the original HD of my Windows 10 64bit PC to a new SSD disk.
VMs I create from scratch on my new SSD drive perform better.
VMs originally created on HD disks and moved to the SSD drive still perform slowly compared to new VMs directrly created on the SSD disk.
What can I to to make my old VMs take advantage from the new SSD drive?
As far as I know of, you don't have to do anything specific to make VMware recognise that the VM is using an SSD.
In VMware Workstation/Player 12.5.x, you can look for the text "rotation rate" in the vmware.log
For a VM stored in SSD, you could see vmware log entries like the following
vmx| I125: DISKUTILWIN32: DiskUtilW32IsATASSDDevice: Reported rotation rate = 1
vmx| I125: DISK: DiskConfigureVirtualSSD: Disk 'scsi0:0' identified as Virtual SSD device.
For a VM stored in a HDD, the rotation rate would be same as what the physical rotation rate of the HDD, in the below this is 5400rpm.
vmx| I125: DISKUTILWIN32: DiskUtilW32IsATASSDDevice: Reported rotation rate = 5400