Hello,
Are you running AVG or Avast antivirus at the host OS?
If so then see:
XP VM suddenly slow, Win 7 fine
for a solution on using both antivirus products along with VMware
If you are running BitDefender 2017 at the host then the only solution that I am aware about is to uninstall and revert to an older version of BitDefender.
--
Wil