[Fyron]

Or, just by being intelligently designed, so as not to be huge and bloaty... For some nice anecdotal evidence:

Even with managing all those torrents on the SE file tracker, my firewall has had a massive 2:16 CPU Time over the last... 2 weeks? of system up-time. Almost always at 0% CPU load. And its one of the best windows personal firewalls out there...

A game is not web traffic, and neither is something like a torrent client. A bloatware AV resident scanner with "web traffic" scanning shouldn't even enter the picture... Hell, my resident AV scanner has exactly half the CPU Time as the firewall (1:08)! It certainly does what it needs to do as a resident AV scanner...

And this is even on a 5-6 year old pentium IV system with its outdated, bulky, slow silicon...