Kaspersky’s standalone antivirus product has been on our A-List since the day of its release, so we expected great things from it. In the event, we found Kaspersky Internet Security to be a powerful package but not one without weakness, and this month it wins on points rather than by a convincing knockout.

First, the good news: in our malware test, Kaspersky Internet Security achieved a superb 98% detection rate, proving that the engine’s top score in our antivirus Labs back in October was no fluke.

Kaspersky also scored a clean sheet in our website exploits test, and its firewall was among the most intelligent we saw, immediately detecting the first attack and automatically blocking further connections to the host from which we’d launched it. It set TCP ports to stealth mode rather than closing them, so while our remote computer could see only one open port (21) on our system we actually had 25 different ports available. The false-positives test went off without raising a single complaint.

Although Internet Security 7 is very good at what it does, we noted that it was its malware-detection abilities, rather than any sophisticated authentication system, that kept us safe on the web: we missed the reassurance of McAfee’s SiteAdvisor. Antispam performance was average, too, and while the suite’s impact on startup time is pleasingly minimal, its RAM footprint is among the largest in this Labs. There’s also a known bug in Vista, exposed by Kaspersky’s routines, that can cause out-of-memory errors when copying large numbers of files: you’ll need to contact Microsoft for the hotfix.

For all these reasons, you might want to consider other products, such as Eset’s Smart Security. Yet for most users the decision boils down to which package keeps you safest, and this month Kaspersky came first or joint-first in our malware-detection, website-exploit and firewall tests. So, while it isn’t as lightweight or feature-packed as the competition, Kaspersky Internet Security has to take the crown.