A bump to the frontside bus and a smidge more L2 cache can safely be classified as a minor update. But even slightly improved specifications, when they come at a lower price than those they replace, are appreciated. Last September, we tested the highest-end 24-inch model, which carried a baseline price of AU$3,339 and featured Intel's 2.8GHz Core 2 Extreme X7900 processor. We're happy to report that the new AU$2,399 iMac sped past the previous model in CNET Labs, though it features roughly the same specs: a 2.8GHz Core 2 Duo processor, 2GB of faster 800MHz RAM, a 320GB hard drive, and a midrange ATI Radeon graphics card. What's changed is that this model uses a Penryn-class processor that serves up 6MB of L2 cache, compared to the 4MB the previous Merom-class chip provided, while operating on a faster 1,066MHz frontside bus — up from 800MHz.

The biggest upgrade comes with the top-of-the-line iMac, the $2,999 model that sees the iMac top the 3GHz mark with 3.06GHz Core 2 Duo chip. That model also features a 512MB Nvidia GeForce 8800 GS graphics card. The 3.06GHz chip is an AU$300 upgrade on the lower-end 24-inch model we reviewed here, while the GeForce card adds AU$220 to the bill.

Contrary to earlier reports, the 3.06GHz chip is not the Core 2 Duo X9100, which is expected out later this summer when Intel launches its Centrino 2 (aka Montevina) platform. Instead, it's another Apple exclusive from Intel, which operates at the same clockspeed and on the same 1,066MHz bus as the forthcoming X9100 chip, but at a higher wattage. The updates the iMac received aren't game changing by any means, but they certainly do enough to maintain the iMac's Editors' Choice award and a strong recommendation among all-in-one PCs and mainstream desktops in general. In fact, we rate it higher than last year's model because the 24-inch iMac finally includes a graphics upgrade.

The design remains unchanged from last September's iMac models, which marked a change from the white Lucite design to the brushed-aluminium-and-glass chassis. For more on the design, please see our full review of the 20-inch iMac that introduced the new design last August.

We were impressed with the 24-inch iMac's showing last year in the labs, and this latest update showed marked improvement on our multitasking test as well as with CineBench. We weren't surprised to see iTunes performance stay the same, since it's largely dependent on CPU clockspeed. What we didn't expect was a 22-percent increase on our multimedia multitasking benchmark compared with that of last year's model, which was already way ahead of Dells' and Gateway's all-in-one PCs. On CineBench 10, a 3D rendering test that taxes the CPU and graphics subsystems, the new iMac outpaced the older 24-inch model by eight percent, which is about the margin we'd expect between two systems released seven months apart. This iMac's faster frontside bus, faster memory, and larger L2 cache each plays a role in its improved performance over last year's model, as does the new version of Leopard (10.5.2), we suspect (we've experienced some problems with our Photoshop CS3 script recently, on this and other systems, so unfortunately we have no Photoshop results to report at this time).

We no longer report Quake 4 scores, having moved our 3D gaming benchmarks to more recent games for our desktop reviews. We made an exception in this case, however, and were again surprised to see that this new iMac outpaced the older model by a healthy margin, when both use the same 256MB ATI Radeon HD 2600 Pro graphics card. Where the older model posted a meagre 33.7 frames per second at 1,024x768, the newer iMac achieved a framerate of 86.3fps at the same resolution. And when we bumped it up to 1,280x1,024, we still got a very playable 76.8fps. Better news for gamers is that the iMac now gives you the option to upgrade to a more powerful GeForce 8800 GS card.

CineBench
(Longer bars indicate better performance)

Rendering multiple CPUs

Rendering single CPU

Apple iMac (24-inch, 2.8GHz, 2008 model)

6180 

3244 

Apple iMac (24-inch, 2.8GHz, 2007 model)

5709 

3035 

Apple iMac (20-inch, 2.4GHz)

4624 

2599 

Dell XPS One

4507 

2368 

HP Pavilion Slimeline s3330f

4316 

2247 

Apple Mac Mini

4069 

2168 

Gateway One

3787 

1998 

System configurations:

Apple iMac (20-inch, 2.4GHz)
Apple OS X; 2.4GHz Intel Core 2 Duo T7700; 2GB 800MHz DDR2 SDRAM; 256MB ATI Radeon HD 2600 Pro graphics chip; 320GB 7,200rpm hard drive

Apple iMac (24-inch, 2.8GHz, 2007 model)
Apple OS X 10.4.10; 2.8GHz Intel Core 2 Extreme X7900; 2GB 667MHz DDR2 SDRAM; 256MB ATI Radeon HD 2600 Pro graphics chip; 750GB 7,200rpm hard drive

Apple iMac (24-inch, 2.8GHz, 2008 model)
Apple OS X 10.5.2; 2.8GHz Intel Core 2 Duo; 2GB 800MHz DDR2 SDRAM; 256MB ATI Radeon HD 2600 Pro graphics chip; 320GB 7,200rpm hard drive

Apple Mac Mini
Apple OS X; 2.0GHz Intel Core 2 Duo; 1GB 667MHz DDR2 SDRAM; 64MB (shared) Intel GMA 950 integrated graphics chip; 120GB 5,400rpm Hitachi hard drive

Dell XPS One
Windows Vista Home Premium; 2.33GHz Intel Core 2 Duo E6550; 2GB 667MHz DDR2 SDRAM; 256MB ATI Mobility Radeon HD 2400 graphics chip; 500GB 7,200rpm hard drive

Gateway One
Windows Vista Home Premium; 2.0GHz Intel Core 2 Duo T7250; 3GB 667MHz DDR2 SDRAM; 256MB ATI Mobility Radeon HD 2600 XT graphics chip; 500GB 7,200rpm hard drive

HP Pavilion Slimline S3330f
Windows Vista Home Premium; 2.8GHz AMD Athlon 64 X2 5400+; 2GB 667MHz DDR2 SDRAM; 256MB (shared) Nvidia GeForce 6150SE integrated graphics chip; 500GB 7,200rpm Samsung hard drive