With new version memory usage immediately after bootup:

Avast Antivirus Service:
InMemKB 8052
PrivateKB 6946
TotalKB 19,808

Avast Email Scanner:
InMemKB 4644
PrivateKB 3844
TotalKB 15,008

Avast is set up to run Internet Mail and Standard Shield.

Note: the changes to the new version “reduced overall memory footprint of avast modules”.

I only took readings for internet mail and standard shield for the new version and previous version so I have no data for the overall memory footprint before and after.