Just did a manual update...
...and sure enough avgmfapx started running at 50-85% of CPU!
Also, the 65 MB file took about 15 min. to download (guru.avg), which translates into a 0.5 Mbps speed! All the while my computer was of course not usable.
The way I see it AVG, if you're gonna have a slow server like that, then at least make sure the update executable doesn't take over the system!