It doesn't slow down my computer. I've got 1.5gb ram, put that's standard imo so that doesn't make any difference. I even sometimes run it on my 256mb laptop lol but it slows only a little bit...however I recommend that you get it and try it.
Get it, try it and see whether you like it. If not, then just change it!
Also runs fine on mine, and it IS a proper AV....
People have to understand that software runs differently for different people. Lots of people admire NOD32, but when I installed it, it ran really slowly and hogged resources (i have a beast of a pc by the way)
Kaspersky was great. Mcafee was utter rubbish (started using 100% cpu).
Norton is a massive no no, dont install that whatever you do. Its utter bull.
As long as you have either AVG, NOD or Kaspersky you will do fine
AVG does have antispyware and other things as well which is why its a keeper in my books.