I am also seeing the same high CPU usage problem since the last update. My phone is SE Xperia Arc and avast has been pretty good so far. With the current update, the phone has developed serious lag and Android Assistant shows avast as consistently consuming 30-40% cpu cycles. I have also noticed, but not tracked/recorded that this behavior generally occurs more in the morning hours… I will also probably go back to an older version until this issue is resolved.