Intel Core i3, i5, i7 laptop CPUs explained: i-Caramba

Intel's dumped its Core 2 range and busted out some brand-new processors, known as Core i3, i5 and i7, which are designed to simplify the task of choosing a laptop and ensure whichever PC you pick is even faster and more efficient than the model it replaces.

We're hugely excited about these chips, primarily because most of them have the ability to automatically overclock themselves for extra performance, or reduce their clock speeds to preserve battery life. In addition, each comes with a graphics processor built directly on to the CPU. According to Intel, the new onboard GPU has 20 per cent more shaders -- an important component in the fight against juddery 3D. This, we're told, can improve graphics performance over existing Core 2 integrated graphics by some 70 per cent.

The Core i3 is the baby of the group, but don't let that fool you: it's a potent performoer in its own right. Two flavours are available -- a 2.13GHz Core i3-330M and a 2.26GHz Core i3-350M, both of which are dual-core and have a 1,066MHz front-side bus that makes the most of 1,066MHz memory.

On the surface, it doesn't appear all that different to the standard Core 2 Duo range, but look deeper and youll see the i3, like its i5 and i7 brethren, features Intel Hyper-Threading -- a technology that allows four-way multitask processing. Whereas each individual processor (or core) on models in the Core 2 Duo range could handle just one processing thread at a time, Hyper-Threading allows the Core i3 to run two processing threads simultaneously on each core -- allowing it to perform four things at once, instead of the usual two.

The Core i5 is the next step up on the ladder. The chips are fundamentally identical to the i3, but a wider variety of clock speeds are available, starting with the top-end 2.53GHz i5-540M. A couple of 2.4GHz options are available in the form of the i5-520M and i5-520E, both of which are identical aside from the i5-520E's support of error correction code (ECC) memory -- a type of RAM typically used in servers. Finally, Intel also provides a 1.06GHz Core i5-520UM processor, which is designed for ultraportable laptops.

It's worth noting that much of the time, Core i5 chips won't actually run at their core speeds -- they'll go even faster. This is thanks to a new feature known as Intel Turbo Boost -- a fancy system that automatically overclocks the processor to a faster frequency, provided it's running below its limits for peak power, current and temperature. The 2.53GHz i540M can run at up to 3.06GHz, while the 2.4GHz i5-520M will reach up to 2.93GHz. The low-voltage Core i5-520UM scales from 1.06GHz to a plucky 2.13GHz.

Core i7, the pumped-up, muscle-bound hunk of the range, really takes advantage of this particular feature. Its bottom-rung Core i7-820QM -- a chip designed for thin-and-light laptops -- can jump from 1.20GHz to a stonking 2.26GHz with Turbo Boost enabled. Most impressive of all though, are the Core i7-720QM and i7-820QM --- the only quad-core parts in the family. The former can leap from 1.6GHz up to 2.8GHz, while the latter goes from 1.73GHz up to a jaw-dropping 3.06GHz. If that's not enough for you, consider the gaming-oriented Core i7-920XM. This beast has a base frequency of 2GHz, but overclocks itself by 1.2GHz to reach a startling 3.2GHz.

Its all clever stuff, we think you'll agree, and hopefully it'll give you an approximate insight into how these new-fangled chips compare to one another and what sort of performance you can expect. As always, we're planning to give you full, hands-on reviews of laptops sporting these chips in the very near future, so keep your eyes peeled firmly in this direction.