question about avastsvc at bootup

Hello everybody,

I am using last avast 2015 version on windows 8.1 64 bit

during boot process i can observe a period of disk thrashing (100% busy with slow transfer rate)

on resource monitor i check i/o and i can see a lot of
avastsvc process ,each one reading in \windows\system32\catroot files with in file name
“package 1 for KBxxxxxx”
because i have 147 KBxxxxxx installed there is several pages of avastsvc process on resource monitor

theses 147 avastsvc processes take at least one minute to complete and start disk Thrashing

I can’t understand if theses process are normal virus checking activity from avast or not
and if it is possible to sérialize it

Best regards