The antivirus is one of the most important software that should be on installed on any computer. I doesn’t matter if you’re using Windows XP, Vista or Linux. “Fences” like the UAC or sudo aren’t that strong because they’ll just ask if you want to allow a program to run in privileged mode, they won’t tell you what that program will do.

For the last 5-6 years, I’ve been a fan of Kaspersky Antivirus and I recommended it to everybody. Many friends replied that it uses to many resources and the PC runs slow, but the trick was to set the scanning to “performance” (low). That meant a faster system, with insignificantly less security due to the excellent algorithm. It also had some optimizations, like scanning only the modified files (not all) before running them.

But since the last revision, I noticed that it started to leave a heavier footprint on my system, especially on the web and mail scanning. It takes 30 seconds to 5-6 minutes to load a youtube video or the LinkedIn page. Even with the web scanning turned off, it still takes significantly more than with the program turned off.

Jeff Atwood, from CodingHorror.com realised this several months ahead and provides performance data from the quoted study:

Percent slower
Boot CPU Disk
Norton Internet Security 2006 46% 20% 2369%
McAfee VirusScan Enterprise 8 7% 20% 2246%
Norton Internet Security 2007 45% 8% 1515%
Trend Micro PC-cillin AV 2006 2% 0% 1288%
ZoneAlarm ISS 16% 0% 992%
Norton Antivirus 2002 11% 8% 658%
Windows Live OneCare 11% 8% 512%
Webroot Spy Sweeper 6% 8% 369%
Nod32 v2.5 7% 8% 177%
avast! 4.7 Home 4% 8% 115%
Windows Defender 5% 8% 54%
Panda Antivirus 2007 20% 4% 15%
AVG 7.1 Free 15% 0% 19%

As you can clearly see, the performance decrease is significant, especially for all you Norton AV users. But this is not all!

As Jeff points out in a later post, antiviruses are becoming less and less effective. Just look at the detection rate of new viruses, in the study done by Andreas Clementi [av-comparatives.org]. It’s between 3% and 81%, with an average of less that 40%.

Looking at these numbers, the idea of dropping the AV security doesn’t sound that bad. But it is bad! Why? Well, because from what I’ve seen, most infections explode after the solution is available. I myself got infected this year (the only time I know I’ve been infected unintentionally) with a virus +6 months old. And it happened because I did not have an antivirus.

The question regarding performance vs. security in an antivirus still stands. I am seriously thinking of installing a “better” AV. I think I’ll browse the net for reviews and perform some tests on the candidates, but if you know something good, please tell me.