intel core i7-620m

Enter, therefore, Intel's Arrandale processor. That's the codename for the mobile version of essentially the same CPU-GPU combination found in desktop Core i3-500 and i5-600 processors.

Except in mobile format, Intel will be applying the full whammy of Core i3, i5 and i7 Mobile monikers depending on differentiators such as clock speeds and cache memory.

Two chips in one

What all Arrandale chips share is a two-chip construction under the hood. Just like the Clarkdale desktop version, the first chip is a 32nm item housing a pair of execution cores and a helping of cache memory.

The second uses Intel's older 45nm transistors and packs the memory controller, PCI Express and that controversial graphics core.

Our review model is the high-end Core i7-620M, a 2.66GHz chip with 4MB of cache memory that clocks up to a maximum of 3.33GHz in Turbo mode (we also have a review of the closely related but more affordable Core i5-540M).

Serving as a yardstick we have an example of Intel's existing Core 2 Duo mobile processor in 2.4GHz trim. Not the fastest Core 2 Duo available, therefore, and not a like-for-like comparison in terms of operating frequencies.

Pulverising performance

Despite that, the advantage the new processors carve out is still stunning. The 620M is twice as fast in our HD video encoding and professional rendering benchmarks. Memory bandwidth has likewise ballooned from under 6GB per second to nearly 10GB per second.

Shift the emphasis to high-definition video decoding and the new chip is just as impressive. A 2.4GHz Core 2 struggles to cope with the BBC's 720p iPlayer streaming video, for instance, dropping frames and running at around 90 to 95 per cent CPU time.

Intel's new mobile machine shrugs that task off in return for just 40 to 50 per cent of available CPU resources. Stunning.

If you're wondering how this is possible, it's down to features such as HyperThreading that come with the Nehalem-class architecture which underpins Intel's latest mobile chips. It all adds up to what Intel rightfully claims is quad-core rivaling performance from a dual-core processor.