Nope no memory slow downs
at least not yet for me and I'm using XP on a net-book
it starts couple of tasks which can be seen in the Taskmanger (Ctrl Alt Delete)
and takes up a total of 10MB combined
It light weight and easy to handle
Good enough for me
Though there are others like NOD32 and Avast Anti Virus But I prefer AVG as
Nod32 is too powerful and I like keeping Trojans and Hacking software on my PC
And Avast Anti Virus is for people with Broad band and Fast DSL connections as its an Online Anti Virus ... always needs to be connected to the net to scan and use its scanners online
SO AVG for me is the best so far... under anti viruses
if you need only Spyware Removal software then I would Reccomened Spyware Doctor
I used to have the latest cracked versions of it but there came a bulid of it that slowed down the PC but later new and latest versions fixed that problem But I'm atm satisfied with AVG