Design & Hardware: almost identical to the 21.5 inchApart from being bigger and heavier, there are a few other design differences between the 21.5 and 27 inch models. We still don't like the super-shiny screen and the glossy bezel that picks up the slightest finger and palm print, but the excellent overall design just doesn't seem to age.
The keyboard the same size as the keyboard on a MacBook Pro, and it's fairly pleasant to type with—even if we think it would be a little more comfortable if it was slightly bigger. As it is though, gamers (oh yes, you can play games on a Mac) will no doubt prefer to invest in a different model, particularly because the Fn key is to the left of the Control key, so you may end up pressing the wrong one by accident. Note that when ordering your iMac, you can instead choose a keyboard with a numeric keypad, for an extra charge, although this is wired rather than wireless.
The Apple Magic Mouse included is just horrible to use. Although it's already pretty rubbish for office computing, it's likely to have gamers tearing out their hair. For a bit more cash, you can upgrade to the Mighty Mouse although, to be honest, that's not much better. A different manufacturer's model is the only real solution if you want a decent mouse for your iMac.
If you prefer you can order the Apple Magic Trackpad, which is much nicer to use than either of Apple's mice, instead (no extra cost) or as well (£59) as the Magic Mouse. Note however that you can get a 5-star rated mouse for a good deal less.
The webcam (1280 x 720 pixels) gives good-quality results. The exposure is decent and movements are followed and recreated well. In lighter areas the image is very detailed but in darker areas of the scene a certain amount of detail is lost, as is the case with most webcams. That said, this webcam is still perfectly fine for day-to-day use.
As with previous generations of iMac, Apple's new all-in-one is very quiet, both when idle and when working hard.
If you bring your ear up to about 30 cm away from the iMac, you'll hear a slight buzzing, but this is no longer audible when you move further away.
Hot air is released from the top right of the rear casing. The overall temperature is kept in check nicely though, and we've got no complaints on that front.
Temperature readings from the 27" iMac with the components working hard. Readings taken with the Fluke Ti25 camera.
Like the iMac 21.5 inch 2011, this version has a FireWire 800 port, four USB 2.0 ports, an SD card reader (on the side), an RJ45 port (Ethernet) and two optical mini-jacks (in and out). The only change to the connections is that the 21.5 inch only has one Thunderbolt port instead of two on the 27 inch. This type of port can be used to connect compatible external storage peripherals or an extra monitor.
Although it's not the first time we've seen this, we still don't like the fact that Apple has chosen not to include any of the more common video connections, such as DVI or HDMI ports. That means that if you have any monitor other than Apple's LED Cinema Display, you'll need an adapter (also sold by Apple) in order to connect it to your iMac.
On the lower edge of the screen, there's a compartment held closed with three screws houses four RAM slots. To gain access to the rest of the components you'll need to take the screen apart, something we do not recommend you do ... even if behind the shiny screen front there's a matte panel that's just dying to get out.
||DVD drive and SD card slot
Processing Power: an effective CPU even without hyperthreading
Like the 21.5 inch, the 27 inch has a Core i5 (4 core) processor in its basic configuration. Although a little more powerful than that used for the 21.5 inch, it doesn't support hyperthreading either.
Hyperthreading enables the execution of an additional thread for each physical processor core. The Core i7s with this feature therefore have 8 virtual cores (4 physical cores x2) for applications that are optimised for multithreading (Handbrake, iMovie, etc).
Note that you can choose a a Core i7 for the iMac 27 inch on the Apple site, but this will take your basic pricing up to £1649.
In spite of this, the 27" iMac still does a very good job. Its Core i5 processor keeps day-to-day computing and multitasking smooth and fluid. Similarly, for more power-hungry applications like video editing software or 3D modelling programs, you won't have to twiddle your thumbs for too long when the iMac gets to work. .
Below are the results of the Xbench benchmark test for this year's iMac compared with older models. The 27 inch, as to be expected, is more powerful than both the 21.5 inch and the 2010 generation.
3D Gaming: a good graphics cardIn spite of the card's decent gaming capacity, don't expect to be able to enjoy native resolution (2 560 x 1 440 pixels) in all titles. If you drop down to 1920 x 1080 pixels however, you have a good few more options (Starcraft 2, the latest Call of Duty, NFS, Colin McRae: DIRT 2 ...) and you won't need to make many concessions with your graphics settings. With the very demanding titles (Metro 2033 and Crysis) you will have to make much bigger concessions here, or lower the resolution a bit more.
Audio: very goodThe sound output hasn't changed much in this new iMac. Then again, with a headphones output that can easily reach a 90 dB signal-to-noise ratio and with no crosstalk issues, it was already pretty impressive. The line-in is of the same calibre too.
The speakers are located on the lower edge of the computer screen and they work well, with an output that's crisp and clear. Beware though, as the output can be affected by where you choose to position your iMac.
Finally, an optical S/PDIF input and output are available too.