Sales of Apple's latest operating system, "Snow Leopard", or Mac OS X 10.6, have beaten those of the company's last two OS releases in the first 2 weeks on the shelves.

The US figures, from the NPD Group from both online and retail shops, although not revealed in detail, are said to show that Snow Leopard has sold twice as many copies in the first 2 weeks as Leopard did back in 2007, and four times as many as Tiger, in 2005.

Although increased Mac sales must have something to do with the rise, an NPD analyst suggests it's Apple's competitive pricing that's helped the sales success.

A single licence for Snow Leopard is $29 in America (here in the UK it's £25). In comparison Microsoft's latest OS, due to be released in October is priced at $120, or in the UK £80.

"Apple clearly demonstrated that aggressive pricing policies in this economic environment generate an outstanding consumer response", said Stephen Baker, NPD's analyst for retail software sales.