Today's best antivirus software outperforms last years software in more ways than you might think.
faster scanning
less CPU usage
lower memory requirements
updated virus/threat detection
better heuristics (for detection of new, unnamed viruses)
In our tests, we look at each of these factors (and lots of others, too.)
Then, when we're calculating the scores, we weight the scores so
that the most important things antivirus software should do, like
protect against viruses, affect final scores the most.
Category Scores and Overall Rating Scores are calculated using weighted
averages. We put the highest value on the most important items within a
Category. This makes scores more accurate since they reflect what's
important in the real world.