Apple iMac 3.06 GHz review

The hardy iMac, which was first announced to the world a decade ago this summer, is responsible for a significant chunk of Apple's success.

Back in 1998, you'll remember that it was the brightly coloured, translucent iMac that reaffirmed Apple's reputation as a hot design house and groundbreaking computer-maker in one.

It cut out swathes of market share for the firm, just when Apple needed a hasty financial shot in the arm, and went on to become an iconic product - the root of all other products with the 'i' prefix.

Apple's all-rounder desktop

Blooming out of those halcyon days into more recent years, Macs have moved out of the art department and into the mainstream, and this widespread adoption has been a joy to watch. Today, Apple has some 20% of the US consumer market stitched up.

Our last iMac review, which was a first look at the aluminium body some nine months ago, was easily the most-read article on TechRadar when we posted it up. It got serious hits because the audience for the iMac is so wide; people regard it as both a home computer and an office workstation. It has an air of accessibility and power by the bucketload.

This month, the iMac has been significantly updated again to help maintain its edge. It's a generous upgrade. Beyond bringing in Intel's hot little Penryn processors, Apple has rewired the guts of the iMac to dramatically boost the speed that data can travel between the cores and other components, while also updating the RAM, graphics ability and hard drive specs.

The machine we're reviewing here is the top-end 3.06GHz 24-inch iMac.

Impressive specs

Apple has stuck with the 20-inch and 24-inch sizes. You can get a better look at the current specs on Apple's website than we have space for here, but in a nutshell, the Penryn processors are entirely new to iMacs, more power efficient and faster than the Merom chips they replace.

The system bus, which ferries data to and fro between the processor cores and other components, has had its bandwidth widened from 800MHz to 1,066MHz, so data can be routed faster, and the standard RAM allocation is now 2GB on all models except the entry level 20-inch iMac, which has 1GB as a single stick.

There are two RAM slots in each iMac, allowing for up to 4GB of RAM. RAM is still considerably cheaper to buy and install yourself than let Apple do it.

The fastest iMac

Our test model is the first 'non-Pro' Mac to breach the 3GHz glass ceiling and breathe the same rarefied air as the Mac Pro. It also features a new, different graphics card to the other iMacs.

The 3.06GHz 24-inch iMac uses the NVIDIA GeForce 8800 GS, which is an only slightly tuned-down version of the cracking NVIDIA GeForce 8800 GT card used in the Mac Pro, but with the same whopping 512MB of dedicated RAM.

The only difference we can find between the GS (iMac) and GT (Mac Pro) is a slightly lower clock speed (550MHz as opposed to 600MHz). What's 50MHz between friends?

The faster chips, new graphics card and pipes that surround it have improved the graphics performance, and combine to make it one very competitive computer for playing games and excellent for all aspects of video and graphics.

The display is great, too; the 24-inch iMacs feature 8-bit TFT widescreens that achieve millions of colours without employing dithering techniques, unlike the 20-inch iMacs with their 6-bit displays.

Generous feature set

The exterior of the iMac remains unchanged. This is the same all-in-one aluminium design as before, with built-in webcam, IR remote and generous screen size and connection options. The software includes the Leopard OS and iLife '08 package, plus Apple's excellent Front Row media application.

As you might expect from a newly rewired computer with faster processors and new components, the new iMac is considerably faster than predecessors and zips right through chunky processing commands.

We benchmarked the CPU and hard disk and threw in an audio-encoding test. We then tested the graphics card and processor with 3D rendering tasks and movie encoding.

Putting it to the test

Compared to a 2.0GHz aluminium iMac with equal RAM from eight months ago, the new 3.06GHz iMac scored some 60% faster in our CPU test - testament to the Penryn prowess and value of the FSB upgrade. This score was also 3% ahead of a year-old, entry-level 2.66GHz Mac Pro, and only marginally behind an eight-core 2.8GHz Mac Pro with equivalent memory.

This is not to say that the iMac and Mac Pro are equally matched for heavy rendering and graphics work. It's more that you will only see the Mac Pro accelerate away from the iMac when all its extra cores are being driven hard by software and workload that can properly exploit them.

Our audio-encoding test produced an anomaly. Committing a CD to iTunes as high-quality AAC files took only 5 minutes, 49 seconds on the 20-inch 2GHz machine but 7 minutes, 43 seconds on the 24-inch 3.06GHz iMac. After triple checking, we couldn't explain why.

Perhaps Apple's rewiring and repowering efforts reduced the optical drive's comparative efficiency as a side effect of optimising the rest of the system. Answers on a postcard, please.

Buying advice

The new 3.06GHz 24-inch iMac is a wonderful Mac that continues the strong tradition. The screen is gorgeous and the graphics ability phenomenal for what some people still pigeon-hole as a 'family' Mac.

With the entertainment software package that comes bundled for free, and the stability of the OS, this is an excellent choice for general-purpose computing or even hard number-crunching, and at 24 inches, this could easily be your new TV, too.