AvastSvc.exe memory usage multiplied when opening many tabs

AvastSvc.exe memory usage multiplied when opening many tabs at Win8 x64, only have file shield, behavior shield, web shield installed, and web shield using default settings.
:o :o :o

http://is100.imagesocket.com/images/2012/12/22/2560298-k3hl.png

http://is100.imagesocket.com/images/2012/12/22/2560299-n1o3.png

This looks normal. Each browser tab necessitates a corresponding additional expansion of the Web Shield’s memory footprint.