Apple iMac 27in (2011 edition) review

The iPad and iPhone may have been making all the headlines in recent months, but Apple's Mac computers are also going strong and have racked up almost a 30 per cent increase in sales in the past year.

To keep up that momentum, Apple recently overhauled its laptop range, introducing the new high-speed Thunderbolt I/O technology developed with Intel. Apple has now turned its attention to the iMac desktop machines, claiming that this new range represents a real step forward in terms of power and performance.

The previous iMac line-up primarily focused on Intel's i3 processor, with just a single top-of-the-range model offering either an i5 or i7. That's all changed now, as the new quad-core Sandy Bridge i5 processor is standard in all four models in the new iMac range.

The entry-level point stays at £999 for a model with a 21.5in screen, but the 3.06GHz i3 processor that was previously on offer has been replaced by an i5 running at 2.5GHz. Graphics performance also gets a boost as the old AMD Radeon HD4670 has been replaced with the newer HD6750M model, equipped with 512MB of VRAM.

That model's 4GB RAM and 500GB hard drive remain the same, but there are some other typical Apple flourishes thrown in for good measure. The built-in webcam now provides 720p high-def video capture for use with Apple's FaceTime video chat software, and Apple informed us that FaceTime uses a 'media engine' component built into the i5 processor to handle the high-def video processing, leaving the primary processor to handle other tasks at the same time.

The screen itself also includes an ambient light sensor that allows the iMac to automatically adjust the screen brightness to suit the lighting in the room. And, if you want, you can swap the standard wireless mouse for one of Apple's multi-touch Magic Trackpad gadgets for no extra cost.

For £1,249 you can tweak the i5 up to 2.7GHz, double the hard disk to 1TB, and upgrade the graphics to the Radeon HD6770M. However, we reviewed the next model in the range, which has the same basic specs but increases the screen to a luxurious 27in and comes in at £1,399.

There's also a top-of-the-range 27in model, which costs a hefty £1,649 and includes an i5 running at 3.1GHz and a Radeon HD 6970M graphics card with 1GB of VRAM.

There are optional i7 upgrades for some of these models, which will add a further £160 to the basic price, and it's also possible to add a 256GB SSD drive alongside the standard hard drive for another £480.