Symantec has released the 2008 version of its Norton Internet Security and Norton Antivirus applications.

As with last year's releases, the security company has placed a strong emphasis on minimising the software's impact on PC performance and memory usage.

The result is a slimmer version that scans 39 per cent faster than its predecessor and an interface that runs 22 per cent faster, according to Symantec.

Performance has been a common gripe among users, particularly with low-end systems that can be slowed down significantly by the constant background activity required by security scanning.

Symantec claims to have overcome this hurdle. Citing 'internal performance tests', the firm said that the new software used 69 per cent less memory while performing 12 per cent faster than a group of unnamed competitors.

The company also hopes that the new software will provide extra protection against some emerging malware trends.

A new Browser Defender component aims to reduce the risk of so-called zero-day flaws by preventing web pages from running jumbled JavaScript and ActiveX code. Both are common methods for exploiting vulnerabilities in web browsers.

If malware succeeds in penetrating a system's defences, Symantec is hoping that another new feature will minimise the damage.

An Identity Safe component in Norton Internet Security stores and encrypts confidential information, which is then used to fill in web forms at banking and e-commerce sites.

This will ideally thwart key-logger programs by not requiring the user to enter account or credit card information via keystrokes.

Norton Internet Security 2008 retails at $69.99, while the more limited Norton Antivirus costs $39.99. Release dates and pricing for the UK were not disclosed.