How I selected my Antivirus software for Windows

For a long time, I used AVG free on my machines. Recently, I notice that the memory footprint for AVG was getting large and I wanted to know if there was a better free Anti-virus software out there. There are essentially 3 main free Anti-virus software: Avast!, Avira, and AVG. If you do a google search, you’ll notice tons of post comparing the merits of one over the others. The following links is an actual benchmark that compare the Anti-virus products and were used as reference.
http://www.av-comparatives.org/seiten/ergebnisse_2008_11.php

Click to access antivirus_09-performance-testing-ed1.pdf

http://www.maximumpc.com/print/4230

Memory Footprint Ranking
If you have plenty of memory, you can probably careless about this category. However, a lot of older machine or netbook may have limited memory, so every bit of memory saved counts. Keep in mind I am more interested in idle memory footprint than when it’s scanning.

Memory footprint of the anti-virus product at idle can be ranked in the following order according to the passmark article. I also try installing each product on my Vista machine and verified the ranking.

Product	Memory Usage in Mb
Avast! Antivirus Home	18.05
Avira Antivir free	22.3
AVG Free	56.06

While Avast! And Avira were similar to each other in memory footprint, AVG appears to be using twice the memory of the other two product.

Virus Detection
How well does the three product detect virus. It appears that Antivir is somewhat better than the other. I am not convinced that Antivir is actually that much better, but various post online indicates that its detection rates were better than average.

Product	Detection Rate (from av comparative)
Avira Antivir free	71%
AVG Free	43%
Avast! Antivirus Home	40%

Background Performance
How much performance loss do you suffer running the anti-virus software. Judging from the test results from passmark, the three products are very similar in performance. Differences show up in File Open where AVG and Avira is nearly twice as fast as Avast and file copy where AVG is noticeably slower than the other two products.

The Maximum PC article seems to complain that the AVG had the biggest negative performance.

Scanning Speed Ranking
Of the three products, the scan speed varies by quite a lot according to passmark.

Product	Time (sec)
Avira Antivir free	68.8
Avast! Antivirus Home	116.87
AVG Free	364.2

The Maximum PC article indicated that the Avast is very slow but didn’t provide numbers on how it compare with the other two product.

User Interface
User interface is very subjective, but in my opinion, AVG has the best and clearest interface. Avast is the worse. The interface looks like a media player, which doesn’t quite fit the paradigm of a virus scanner at all. Avira is somewhere in between the two. It’s not great, but at least it works.

Registration
How annoying is the registration process for the Virus. AVG is probably the least intrusive. You are prompted to register, but you do not have to. Avira is similar but throws up a pop-up every times the program updates the virus definition. The most annoying is Avast, which requires you to registered for a license key or the program will expire in 60 days. The key last only a year, so you must registered again next year.

Features
All of the product offers email and spyware protection. Avast also has IM scanning, but does not have scheduled scanning. Unlike the other two product, AVG does not have rootkit protection.

Recommendation
In my opinion, the best free anti-virus is currently Avira Antivir. It has the fastest scan, best detection rate, and second best memory footprint. It’s annoying to get a pop-up on every update, but that is a small price to pay for a free product. I also want the anti-rootkit feature and scheduled scanning since I want to do the scanning while I am not using the machine.