Apple iMac 21.5-inch review (2.5GHz, spring 2011)

Editors' note (October 23, 2012): The 2011 iMac reviewed here has been replaced by an updated 2012 model that offers an all-new superthin design and improved hardware specs (Ivy Bridge CPU, Thunderbolt port, USB 3.0).

Apple's 27-inch iMacs stand out largely because they offer bigger displays than any other all-in-one. The newly updated 21.5-inch iMac has always had a harder time persuading buyers thanks to the glut of 23-inch Windows-based all-in-ones in the same price range. A fast new Core i5 processor helps the most affordable new iMac make a strong case for its performance, and we expect OS X-loyal professionals will appreciate the iMac's added speed and, eventually, its new Thunderbolt data port. Consumers will be less convinced, especially given the iMac's lack of home entertainment conveniences.

As we said in our review of the new 27-inch model, the design of Apple's iMacs remains the most aesthetically pleasing in the industry. The 21.5-inch model has a smaller footprint than the larger one, coming in at 17.75 inches high and 20.75 inches (compared with 20.25-inches high and 25.5-inches wide on the 27-inch iMac), which could make the smaller-screen version one better suited to tight spaces.

Along with featuring the smaller screen among the two iMac varieties, the 21.5-inch model also has a smaller screen than price-comparable Windows all-in-ones. Dell's Inspiron One, HP's TouchSmart 610-series, the Gateway One ZX6000-series, and others all boast 23-inch displays, and some, like Dell's all-in-one, can be had for under $700.

Admittedly, the iMac's display gives up only a diagonal inch-and-a-half in its physical measurements, which is hardly enough to cause a dramatic degradation in its user experience. You could argue that the more compressed pixels will make for crisper image quality, at least when you're sitting up close. The Windows side of the debate might similarly point out that larger screens lend themselves to better viewing from a distance, which you might want from an all-in-one designed, as many Windows all-in-ones are, for home entertainment. Both sides have a point, and the arguments of the screen-size debate extend through to the 21.5-inch iMac's features comparison as well.

The Dell Inspiron One 2305 we reviewed in November is now six months old, but it remains Dell's highest-end all-in-one offering, with the same specs as when we first wrote about it. Aside from its all-in-one form factor, the Dell and the iMac couldn't be more different.

The Dell's large touch screen, its Blu-ray drive, and its HDMI input make it well-suited to serving as a digital entertainment kiosk. You could set it up in a den, a bedroom, or on a kitchen counter and use it to consume almost any kind of digital media. The HDMI input in particular lends the Inspiron One great versatility, letting you use it as a standalone display for a game console or a cable box. With the help of an extra, expensive adapter you can use the new Thunderbolt port on the iMac the same way, but you still don't have a touch screen to simplify media controls, and the lack of a Blu-ray drive in the iMac potentially gives you another device you must connect to replicate the same streamlined digital media hub.

On the other hand, the iMac makes a far superior computer for producing digital media or tackling any other performance-dependent task. The iMac's new Intel Core i5 2400 processor is a generation ahead of the AMD Phenom II X4 chip in the Dell. The iMac also has a faster, more recent AMD graphics chip. The Thunderbolt port, which replaces the old iMac's MiniDisplay Port, will be important also, when compatible storage arrays, video hubs, and other devices debut this summer that take advantage of its fast, bi-directional data transfer capabilities.

CineBench 11.5
(Longer bars indicate better performance)

Rendering Multiple CPUs

Rendering Single CPU

Gateway FX6850-51u (3.4GHz Core i7 2600, Spring 2011)

6.89 

1.53 

Apple iMac 27-inch (3.1GHz Core i5 2500, Spring 2011)

4.88 

1.3 

Apple iMac 21.5-inch (2.5GHz Core i5 2400, Spring 2011)

3.96 

1.25 

HP Omni 200 5380qd (2.8GHz Core i5 760, Spring 2011)

3.93 

1.11 

Dell Inspiron One 2305 (2.4GHz Phenom II X4 610e, Winter 2010)

2.71 

0.69 

Apple iMac 21.5-inch (3.0GHz Core i3 540, Spring 2010)

2.59 

1 

Call of Duty 4: Modern Warfare Time demo (fps)
(Longer bars indicate better performance)

1,920x1,080

Apple iMac 27-inch (3.1GHz Core i5 2500, Spring 2011)

79 

Apple iMac 21.5-inch (2.5GHz Core i5 2400, Spring 2011)

39 

Apple iMac 21.5-inch (3.0GHz Core i3 540, Spring 2010)

13 

You get a clear picture of the 21.5-inch iMac's performance superiority from our benchmarks tests. The iMac is faster than Dell's $1,149 Inspiron One 2035 on all of our benchmarks. It's also faster than last year's $1,149 iMac. The $949 HP Omni 200 gives the iMac some difficulty on our Photoshop CS 5 test, which we suspect is due to the fact that the HP has twice the graphics memory of the iMac. The two are also close on the multithreaded CineBench test, likely due to the HP's higher CPU clock speed, despite being a Core i5 CPU from Intel's previous chip generation.