Is the version of AVG fully up to date ?
If it is, I would suspect you may be right.
I noticed that the AVG site has become extremely busy lately, as soon as an update is available people overload their servers with update requests and quite often you can't get through. So I downloaded Avast for a friends PC that I was working on and found it to be very good.
I am sure that the subsription based AVG will be a little better than the freebie though.