Review: Apple's new 21.5-in. iMac

It's an even more stylish all-in-one, but you'll want the Fusion Drive for the most speed.

There's something different about Apple's latest iMac, and it's obvious even before you see it. The peculiarly shaped box it ships in hints at the design changes made to this model, which was unveiled by Apple in October and is only now shipping in significant numbers.

The big difference is the thinner aluminum housing around the screen, which now tapers to just 5mm at the edge -- an amazing 80% reduction in thickness compared to its predecessor. It's immediately noticeable and it looks impressive, especially from any angle in which the side, top, or bottom of the iMac is displayed.

But the changes are more than external. The new iMac -- still available in 21.5-in. and 27-in. screen sizes -- features an Ivy Bridge architecture powered by either an Intel Core i5 or i7 processor, faster graphics chipsets from NVIDIA and an optional solid-state drive/hard disk drive combo that Apple calls a Fusion Drive. This last change stands out as closest to the cutting edge of technology you'll find in the iMac -- but with a big caveat. More about that below.

The new iMac line was unveiled in late October after going almost a year and a half without an update. (The last version arrived in May 2011). Shipments of the smaller model, which starts at $1,299, beganshortly after Thanksgiving -- barely in time for the holiday shopping season. The larger, 27-in. iMac starts at $1,799 and is only now beginning to trickle out.

The sluggish rollout is unusual for Apple, whichstopped selling the previous iMacs before the new ones actually arrived.

Specs and details

The 21.5-in. version comes in two basic models, both of which feature a 1920-x-1080-resolution display. The $1,299 iMac uses a 2.7GHz quad-core Core i5 processor with 6MB of L3 cache and the ability to use Turbo Boost to push the processor to 3.2GHz when needed. The $1,499 iMac has a faster 2.9GHz quad-core Core i5 (also with 6MB of L3 cache) and can top out at 3.6GHz with Turbo Boost. The latter iMac can also be ordered with a Core i7 quad-core chip running at 3.1GHz (with a Turbo Boost speed up to 3.9GHz) for an additional $200.

Both of the smaller iMacs come with 8GB of 1600MHz DDR3 RAM, though you can double the memory to 16GB for $200. But here's the kicker: You can't upgrade the memory after you buy. So if you think you'll want 16GB of RAM down the road, order it that way now. (In contrast, the 27-in. iMac has four user-replaceable memory slots, so you're not locked into 8GB of RAM.) For comparison purposes, the larger iMacs offer more than bigger screens: they cost more, too. The basic 27-in. model starts at $1,799 and comes with the same i5 chip as the $1,499, 21.5-in. iMac. The $1,999 model gets you a Core i5 processor running at 3.2GHz, though you can move up to a Core i7 running at 3.4GHz for $200 more if you need more processing power. You also have more storage options on these models, including a 768GB SSD drive that will set you back $1,300.

All of new iMacs come with a 1TB hard drive and a NVIDIA graphics cards, starting from a GeForce GT 640M in the entry-level model to a GeForce GT 650M in the $1,499 version. The larger iMacs get either a GeForce GTX 660M or a GeForce GTX 675MX to drive the 2560-x-1440-resolution screen. Any of the NVIDIA cards should be enough to power most games and graphics-heavy apps for the life of the iMac.

Rounding out the standard iMac feature list are stereo speakers (which sound pretty good, but won't satisfy hard-core audiophiles), dual microphones (used for noise-canceling when conducting FaceTime video chats or using the built-in dictation), a headphone port (which supports headphone/optical audio output), four USB 3.0 ports, two Thunderbolt ports for peripherals, an SDXC slot and Gigabit Ethernet. There's also a 720p FaceTime video camera, 802.11a/b/g/n Wi-Fi and low-power Bluetooth 4.0.

Design pluses and compromises

The iMac Apple provided for this review is 17.7-in. high and 20.8-in. wide, and weighs a svelte 12.5 lb. As with previous models, the overall look is minimal and clean, with an inch-thick black border framing the screen. Viewed strictly head-on, the new iMac looks pretty much like the last model. But looking at the new aluminum chassis from any other angle showcases how thin the housing is. It's a seriously elegant design ... and clearly a show-off move, done more for ooohs and ahhhs. Credit (or blame) Apple's design guru Jonny Ive.

I say that because the machine's footprint is the same; this iMac won't take up any less desk space than the last model, so the decrease in size and volume is more about form than function.