Using a fully updated ver.4
CPU load is some 25 MB- not great, but not bad either.
The scan speed is just great, and the time it needs to update definitions and program modules incredible.
I also have a licence for the top-of-the- iceberg AV program currently (NOD32), but I use Avast4, as when scanning through folders with lots of comressed files I get some slugginess on responce, even with NOD, while Avast 4 lets the browser respond at a snip.
I will agree that version 4 has still some quasi-beta characteristics, but else it's probably the only AV utility that will do a proper job without letting you notice that you have installed it. And the comparison to v.3 is simply out of place, v.3 was a notorious false alarm addict, while v.4 has simply dropped this bad habbit completely.