PC Advisor has updated its chart of the best antivirus programs. Check out our Top 5 antivirus round-up, or read on for buying advice, and how we test and rank the latest antivirus products.

Malware is evolving faster than ever, so it’s reassuring to discover that the latest generation of antivirus (AV) is better equipped to handle this rapid pace of change. We recommend that every Windows PC runs at least AV, antispyware and a firewall, and that you keep them all up to date. So if you’re not running AV, or if you feel your AV could perform better, there’s a product in our latest antivirus group test that you need. 

In recent years, the technology that powers AV software has changed dramatically. An AV package you purchased a few years ago was able to stop known viruses and other known malware, but brand-new, unknown viruses proved more difficult. Newer products do a better job of stopping them.

For our antivirus group test we teamed up with AV-Test, a respected security-software testing lab based in Germany. AV-Test rigorously tested AV products from a number of leading security companies. In all, 13 programs were tested. In our feature we've presented the Top 5; read reviews of the rest at techadvisor.co.uk

AV-Test’s multifaceted testing procedure looks not only at how well an AV product can detect malware using traditional, largely signature-based methods (that is, employing a database of known malware types), but also at how well it can block brand-new, unknown malware. AV-Test also examines how well a security product can clean up after an infection in the event that a piece of malware does get through.

Our group test focuses on standalone paid-for AV products, rather than free software - although one notable exception is Avira AntiVir Premium 2011, where we judged the free edition as good at catching and nullifying threats as its paid-for counterpart. 

Paid-for AV products usually offer better technical support and more comprehensive protection features than free programs. Internet security suites go further still, offering firewalls, parental controls, identity theft protection and more. 

Regular readers will know that we looked at fully fledged security suites last issue. Some of the names here are the same as those in that round-up and, in general, the AV protection provided by a standalone product is replicated by that in the corresponding suite. However, there are noticeable differences between the two comparative tests. Norton came out top in both, but our group test is far from a straight re-run of the top security suites. 

Antivirus trends

This year, some AV packages come with tie-ins to so-called cloud services, in which fresh information on new threats pushes down from the vendor’s web servers to your PC. This is a trend we’ve begun to see over the past year or two, but it’s really taken off with the 2011 batch of products.

Cloud-based detection takes many forms. In some products, such as Norton AntiVirus, it’s used in reputation-based systems that pull together information on files and file types from users around the world to quickly detect suspicious files. Norton calls its system Quorum, but each company that offers a reputation-based process has its own name for the feature.

In other products, such as Trend Micro Titanium Antivirus, the bulk of the malware detection actually takes place in the cloud - remotely, on the company’s servers, rather than on your PC - with the intention of catching malware sooner and reducing the performance impact on your system. 

Winning ways

Since an AV program is only as good as its ability to block viruses, we based 70 percent of each program’s overall score on its success in malware detection, blocking and cleanup, with features, ease of use and the overall drag on system performance accounting for the rest. 

It was a close race, but Symantec Norton AntiVirus 2011 took our Best Buy award with its excellent malware detection, blocking and cleanup. Kaspersky Anti-Virus 2011 collected a Recommended badge, while BitDefender Antivirus Pro 2011G Data AntiVirus 2011 and Panda Antivirus Pro 2011 completed our Top 5 round-up.

See also: Group test: What's the best antivirus group test?

Antivirus software reviews

Internet security suites

Firewall reviews