Let's deal with the elephant in the room: the Mac mini and iMac are very different products. We're comparing them because some potential Mac purchasers are confused as to their relative merits, and a visit to the Apple website explains why.
These days Apple sells only three types of desktop PC: the iMac, its premium all-in-one; the Mac mini - a stylish, no-frills Mac; and the Mac Pro. The latter is a power tower, aimed as it is named at professionals. All three are grouped under the 'Mac' tab on Apple's site, so you might be forgiven for assuming they are in essence the same thing. They are not.
The Mac mini is the entry level PC for home Mac users, and the iMac tops out the price range. They are both beautifully designed and built, and both run Apple's latest desktop operating system, OS X 10.8 Mountain Lion. But that's where the simularities end.
In this piece we compare the design, components and performance, and connectivity of the iMac and Mac mini. You'll note that we aren't comparing the display or keyboard and mouse. There's a very good reason for this. The iMac is built around a 21.5in or 27in HD, IPS display. It's an all-in-one PC designed to sit on a desk in an office or to replace the TV in your lounge.
The Mac mini comes without a screen - you need to hook it up to a monitor or a TV. And the whereas the iMac bundles the Apple Wireless Keyboard and Apple Magic Mouse, with the Mac mini you get, well, the Mac mini. And that's it.
Mac mini vs iMac: design, size and weight
Reflecting their differing fire power and purposes the Mac mini and iMac have very different designs. The Mac mini is a tiny PC. A slim square box, stylish in its way but more closely resembling a set-top box than a standard desktop PC. It measures 36x197x197mm, and weighs around 1.22kg - like a lightweight laptop. With a single speaker the Mac mini has its own distinctive style, and won't look out of place in your living room, but it is unlikely to stop any traffic.
The current iMac is, by contrast, a stunning looking device. It takes its style cues from high-calibre flatpanel displays, all brushed metal and shiny glass. You may find yourself looking for the 'PC' bit because the iMac houses its high-end components within the display chassis. The smaller, 21.5in iMac measures 450x528mm, and has a stand depth of 175mm. The 27in model measures 516x650mm and has a stand depth of 203mm. They weigh 5.68kg and 9.54kg, respectively. It has stereo speakers and would a fine focal point for any front room.
Mac mini vs iMac: price
The relative prices of the Mac mini and iMac again reflect their capabilities. The Mac mini is the cheapest Apple desktop you can buy. The basic Mac mini costs £499, and the top-of-the-range device is £679. There are configuration options for both that increase the price.
The iMac, by contrast, starts at £1,099. Other models cost £1,249 and £1,499, and the top-of-the-range iMac will set you back a wallet-emptying £1,699 inc VAT...
Mac mini vs iMac: processor, graphics, memory, performance
...which may lead you to ask: 'what does that money buy me?' If you'll allow me, I'll explain.
The basic Mac mini comes with a 2.5GHz dual-core Intel Core i5 processor. Intel's own Turbo Boost technology can clock this chip up to 3.1GHz, and it comes with with 3MB L3 cache. Other options are a 2.3GHz quad-core Intel Core i7 (Turbo Boost up to 3.3GHz) with 6MB L3 cache, and a 2.6GHz quad-core Intel Core i7 (3.6GHz). Both the Core i5 and i7 support Intel's Hyper Threading technology, which allows applications to address four virtual processing cores on the Core i5, and eight virtual cores on the Core i7. Mac mini comes with 4GB of 1600MHz DDR3 memory. This is configurable to 8GB or 16GB. You get onboard Intel HD Graphics 4000 - not as good as a standalone graphics card, but the chief benefit of Ivy Bridge is decent onboard graphics performance.
The Mac mini makes no pretence of being a power PC or even a full-spec media centre, but those specs will make short work of pretty much any task. In processor-intensive tasks that use all of a system's processing cores, the £679 2.3GHz quad-core Core i7 Mac mini was much faster than the £499 2.5GHz dual-core Core i5 Mac mini. MathematicaMark was 72 percent faster on the quad-core system, and Cinebench CPU tests took 51 percent less time to complete than the dual-core model. You get what you pay for, and the Mac mini offers decent all-round performance.
Which brings us to the iMac.
The iMac starts with a 2.7GHz quad-core Intel Core i5 processor (Turbo Boost up to 3.2GHz), and steps up to a 2.9GHz quad-core Intel Core i5 processor (3.6GHz). Both with 6MB L3 cache. You can upgrade the latter to a 3.1GHz quad-core Intel Core i7 (3.9GHz). The top of the range model comes with a 3.2GHz quad-core Intel Core i5 processor (Turbo Boost up to 3.6GHz), also with 6MB L3 cache. By default they all come with 8GB of 1600MHz DDR3 memory, configurable to 16GB or 32GB.
The graphics subsystem this time does offer a discrete graphics card, comprising one of the NVIDIA GeForce GT 640M, NVIDIA GeForce GT 650M, NVIDIA GeForce GTX 660M or NVIDIA GeForce GTX 675MX graphics processors. These are paired with either 512MB or 1GB of dedicated GDDR5 memory.
We tested the cheaper of the two 27in configurations, which costs £1,499. Using Boot Camp we installed Windows 7 to run various Windows benchmark tools. PCMark 7 produced a score of 3367 points, compared to just under 2500 for the 21.5in model running at 2.7GHz. That's pretty good for a machine with a conventional hard disk, rather than a solid-state drive. Its nVidia GeForce GTX 660M graphics processor is a notebook component, but at the higher end of midrange components that manages to produce quite respectable gaming performance.
Running the Mac version of Batman: Arkham City at full 2560 x 1440 resolution with high detail settings is no easy task, but the iMac still managed a playable 25fps. Dropping to a lower, but still fullHD, resolution of 1920 x 1080 pixels let that increas to 35fps, while at 1280 x 720 the iMac could average 50fps.
Testing the least expensive 21.5in iMac, boot time is a relatively sluggish 40 seconds. Using Boot Camp to easily install Windows 7, we ran the PCMark 7 benchmark software and saw a modest score of 2487. This test, as in real life, rewards faster solid-state storage with the higher scores we’re now seeing with SSD-based computers. The GeForce GT 640M graphics card with 512MB of video memory will be fine for a spot of casual gaming. It managed only 27fps when running the Mac version of Batman: Arkham City at full 1920 x 1080 resolution, but we managed to bump that up to a smooth 40fps by lowering the resolution to 1280 x 960.
Mac mini vs iMac: storage
Storage options are, by default, large but dissapointingly slow for both models. The Mac mini comes with either a 500GB or 1TB hard drive. In both cases they are the relatively slow 5400rpm spinning disks. For a price you can add in a 256GB solid-state drive or a quicker 1TB Fusion Drive.
The iMac starts with a 1TB 5400-rpm hard drive. More expensive models bundle a 1TB 7200-rpm hard drive
Mac mini vs iMac: connectivity
Both Macs are bless with excellent connectivity options. The Mac mini has Thunderbolt and FireWire 800 ports, four USB 3 ports and a HDMI connector. There's an SDXC card slot as well as Gigabit Ethernet. Without wires you get 802.11n Wi-Fi, and Bluetooth 4.0.
The iMac offers similar levels of connectivity: SDXC card slot, four USB 3 ports, Gigabit Ethernet, 802.11n Wi-Fi and Bluetooth 4.0. It ups the ante with two Thunderbolt ports, and its Mini DisplayPort output supports DVI, VGA and dual-link DVI - although you have to buy the adaptors for each separately.
iMac vs Mac mini: verdict
Two very different types of product, both the Mac mini and the iMac offer decent performance and excellent build quality. If you simply want a basic Mac to pair with an existing display or even TV, the Mac mini is for you. Choose the iMac only if you want a stylish all-in-one PC to use either as a workstation of media centre.