Apple’s mid-2011 refresh of its iMac range is more than just an incremental update. All four models have moved over to Sandy Bridge processors, the second generation of Intel’s Core-i series. Quad core Intel Core i5s are used throughout, where before all but the most expensive iMac used the less powerful dual core Core i3 chip.

New graphics give up to three times the power of the mid-2010 models, and the FaceTime camera has been upgraded to a 720p, 16:9-ratio FaceTime HD.

Apple iMac 21.5-inch: Build

One thing that hasn’t changed with the 2011 refresh is the form factor. The new iMacs retain their brushed aluminium body and edge-to-edge glass screen. The only change to the bodywork is that the Mini DisplayPort is replaced by a new Thunderbolt port. The SD card reader now supports the SDXC format, but is still uncomfortably close to the optical drive slot. Take care when you insert one.

Apple iMac 21.5-inch: Screen

As you’d expect from an Apple computer, the screen is gorgeous to behold. It’s a 21.5-inch, IPS LED-backlit widescreen, with superb viewing angles and excellent colour reproduction. Its 1920x1080 pixel resolution’s enough for full HD, and a 1000:1 contrast ratio gives you more vibrant colours and deeper blacks. Our only complaint is it’s very glossy, which can cause problems with screen glare. There’s no option for a matte display, even if you configure to order on the Apple online store.

Apple iMac 21.5-inch: Performance

The processor and graphics upgrades have greatly boosted the 2011 iMac’s performance. In our CineBench 3D rendering test, this entry-level 2.5GHz model is over 56% ahead of its predecessor, and it even beat the last generation’s top-of-the-range 27-inch iMac, fitted with a Solid State Drive. In translation, this means your games will run exceptionally quickly: Doom 3 runs at a blistering 169.7 frames a second, with the more modern Call of Duty 4 managing over 86 FPS. Although intended as a home machine, the new iMac is powerful enough to suit many professionals.

Apple iMac 21.5-inch: Connections

Once again, the 2011 iMac gives us a generous four USB 2.0 ports and a single FireWire 800 port. USB 3.0 and the rumoured FireWire 1600 failed to make an appearance, but the Thunderbolt port more than makes up for this. 12 times faster than FireWire 800 and over 20 times quicker than USB 2.0, it can be used for video as well as data. You can connect a second display to your Thunderbolt port, and even link it to a MacBook Pro to use your iMac as a screen for your notebook.

The main problem with Thunderbolt is that there are limited accessories to make use of the technology, but for futureproofing we’re certainly glad of the inclusion. At the moment a video-in connection has to be Thunderbolt-to-Thunderbolt, but we’re told it will be possible for third-party manufacturers to produce connectors to link peripherals that use other video-out formats such as Mini DisplayPort or HDMI.

Apple iMac 21.5-inch: Verdict

We’ve a few relatively minor complaints about the new iMac. Mac Pros aside, the Mac range seems to have been stuck with an 8x SuperDrive for years. We’re never going to get a Blu-ray drive, but it’s time for something faster all the same. There are very few configure-to-order options on the Apple online store too. You can now forego the Magic Mouse in favour of a Magic Trackpad, but this entry-level model is the only iMac in the range where you can’t custom-fit an SSD (or even upgrade your HDD), and Apple will only fit up to 8GB of memory, even though the iMac can take 16GB. Not that buying memory directly from Apple is a wise choice – it’s easy to fit your own, and far cheaper buying from third-party manufacturers such as Kingston or Crucial.

Minor moans aside, the 2011 refresh represents a substantial leap forward for the iMac. Powerful new processors, outstanding graphics solutions and an innovative new Thunderbolt port make the new machines extremely good value for money, especially considering this particular model is £21 cheaper than its predecessor.

Apple iMac 21.5-inch launch date: Out now, link Apple

Apple iMac 21.5-inch price: from £999