If you're debating between sticking with your old antivirus software or upgrading to the 2012 versions,
there are a few things you should know.
While virus signatures can be updated for older antivirus software, the 2012 software has some really important improvements, including:
faster scanning
less CPU usage
lower memory requirements
updated virus/threat detection
better heuristics (for detection of new, unnamed viruses)
Better speed and lower resource use may be important, but nothing is as important as getting the improved heuristics in the latest software.
Better heuristics mean better protection against brand new viruses that haven't even been identified as a virus yet.
Since these "zero-day" viruses are hard to detect, improvements in the antivirus software itself are what can make the difference
between stopping a threat in its tracks and having one sneak onto your computer and damage it.
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.
