For the past month, the latest 27-in. iMac from Apple has been the centre of my digital universe.

Apple updated its iMac all-in-one desktop computers in late July, revamping the internal architecture with updated Intel processors while retaining the line's already successful aluminum-and glass design.

The new iMac comes in two versions: One features an LED-backlit 21.5-in. widescreen LCD with the Intel Core i3 architecture (starting at £999), the other is a massive 27-in. widescreen model, which starts at £1,249 and includes either a Core i3 or a Core i5 chip. (You can also special-order one with a Core i7 processor for more speed.) All models come with 4GB of RAM, at least a 500GB hard drive and a discrete graphics card from ATI.

Luckily for me, Apple sent over the £1,649 27-in. iMac. This particular model has a quadcore 2.8-GHz Intel Core i5 processor, an ATI Radeon HD 5750 graphics card with 1GB of video RAM, and a 1TB hard drive. Apple also included its new Magic Trackpad. There's a lot to like in this computer package.

Connectivity and details

The 27-in. iMac's most prominent feature, of course, is the 2560- by 1440-pixel screen, which is framed by a black border. This border is now customary on most Apple products, from the iMac to the MacBook Pro and displays. The glass is enveloped by solid (and recyclable) aluminum, the case chiseled from a single aluminum block using Apple's unibody manufacturing process. The entire screen swivels up and down on a hinge; the action is surprisingly smooth given the screen's size.

Like the last generation of iMacs, the design is exceedingly clean, almost minimalist: There are no blinking lights, no plastic bits just asking to be snapped off -- and the optical drive is still a slot-loading slit on the right side of the screen. As before, the slot-load drive limits the type of optical disks the iMac can read and write to standard-size DVDs and CDs. No small, odd-shaped discs will work in it.

Apple iMac

Also on the right side of the machine, near the optical drive, is a built-in SDXC card slot. The slot accepts SDXC, SDHC and SD cards used in many digital cameras and video recorders. Note: The slot will not read Compact Flash, Memory Stick, or xD cards, which are also common in cameras and video recorders, though you can still connect peripherals to the iMac using one of the four USB 2.0 ports on the back.

The rear of the iMac also features a headphone jack, an audio-in jack, the aforementioned USB ports, a FireWire 800 port, a Mini DisplayPort and a Gigabit Ethernet connection. Wireless connectivity includes Bluetooth 2.1 and an 802.11n Wi-Fi card that's 802.11a/b/g compatible.

That AirPort card can use either the 2.4 GHz or the 5 GHz bands, depending on your needs. My results indicate 42.5Mbit/sec. download speeds and 21.57Mbit/sec. upload speeds, on average, connected to an AirPort Extreme wireless router. Obviously, your speed will vary depending on your setup and distance from your router.

The iSight camera is located in the middle of the top border of the screen and is nearly hidden in the black border. When the camera is in use, the iMac's only LED -- situated invisibly near the camera -- lights up green. There are a number of applications that take advantage of the built-in camera, my favorite being iChat, which allows videoconferencing with others on iChat or AOL Instant Messenger.

The overall style of the iMac remains unchanged, so if you like the elegant aluminum-and-black-bordered glass look that debuted last fall, you'll love this model, too. But if you're a tinkerer, a do-it-yourselfer, or someone who likes digging into their machines every once and a while, the all-in-one iMac might not be for you. It's not designed to be opened up, unless, of course, you own a pair of industrial-grade suction cups.

And really, do you want to risk breaking that huge expanse of glass just to stick a new hard drive in? In this case, it's better to order your iMac exactly as you want it from Apple than to do upgrades yourself.

Memory is the only really user-serviceable part; upgrading it is as simple as removing three screws on the iMac's lower grille (under the "chin") and sliding in your own modules.

About that display

The iMac ships in a box that's 30 inches wide, 24 inches high and 9 inches deep, so it's not exactly small. I mention this is because of my surprise at how very big the 27-in. iMac seems when you first start using it. The screen initially feels massive and towering, especially if you're accustomed to working on portable devices. (My daily machines are a 15-inch MacBook Pro, an iPad and an iPhone 4.)

A 27-in. display may feel large when it looms in front of you, but you'll appreciate the space as you open more and more windows; the high resolution, vibrant colors and pixel-per-inch count mean everything looks crisp. If you're someone who typically has a lot of programs and windows open at once, the sheer size of the display could deliver an immediate productivity boost. For me, it's been perfect for editing movies in Final Cut Pro or iMovie, viewing and editing photos in iPhoto or with Adobe's LightRoom. Surfing the Web with two browser windows open side-by-side instead of tabbed is a joy.

I've grown quite accustomed to the screen, so much so that I don't perceive it as particularly large anymore; but everyone else who sees it does. Visitors still gawk. And touch. Given the rapid accumulation of fingerprints on the glossy screen, it's no wonder Apple included a cleaning cloth in the box.

It's worth noting that plugging an external video source, such as a MacBook, into the iMac's DisplayPort lets you use the iMac as a monitor. This certainly prolongs its usefulness; planned obsolescence or not, there are many times you could use a spare 27-in. screen -- especially one that is VESA compliant and could be wall-mounted.

I do have one caveat: Watch out for overhead lights, or overly bright lights that are behind you, when you set up the iMac. Lights will definitely reflect off the glossy display. Just make sure you position the iMac so that you don't have to worry about any reflected glare.

Behind the big screen

This is the first lineup of iMacs to completely replace Intel's Core 2 Duo series of chips. In its wake comes the Core i series. The basic 21.5-in. iMac boasts a 3.06-GHz Core i3 processor, though you can choose a 3.2-GHz Core i3 or a 3.6-GHz Core i5 in build-to-order setups. The 27-in. version starts with a 3.2-GHz Core i3, but you have more upgrade options: a 3.6-GHz Core i5, a 2.8-GHz Core i5 like the one I've been using, or a 2.93-GHz Core i7. Those last two are quadcore processors with 8MB of Level 3 cache.

Note: There's been a lot of talk that the Core series chips in iMacs are the low-power models. An Apple representative I spoke to assured me that the processors are the full-powered desktop, not mobile, variants.

This refresh marks the return of ATI graphics to the iMac lineup, in the form of the ATI Radeon HD 4670 on the low end and the ATI Radeon HD 5750 in midlevel and high-end models. All models offer discrete graphics -- even the £999 model. One of the advantages of discrete graphics is dedicated memory, with 256MB or 512MB GDDR3 SDRAM options available on the 21.5-in. models and 512MB or 1GB of GDDR5 SDRAM available for the 27-in. models.