Apple iMac (24-inch, 2.8GHz)

The 24-inch iMac's striking design and impressive performance compare favorably to its smaller 20-inch sibling. In addition to a larger screen size, the 24-inch model offers higher-end configuration options and, of course, a higher price tag. The 24-inch iMac comes in two standard configurations. The $1,799 system includes a 2.4GHz Core 2 Duo processor, 1GB of memory, and a 320GB hard drive; the higher-end configuration costs $2,299 and comes with a dual-core 2.8GHz Core 2 Extreme CPU, 2GB of RAM, and a 500GB hard drive.

We tested the fastest-available, 2.8GHz version with the optional 750GB hard disk, which added another $150 to the price tag, bringing the total cost of our configuration to $2,449. For more on the design, features, and service and support of the fourth-generation iMac, check out our in-depth review of the 20-inch, 2.4GHz iMac.

When we tested the 20-inch, 2.4GHz iMac last month, we came away impressed by its application performance, with it more than holding its own against competing Windows-based, mainstream desktops. The same can easily be said for the 24-inch, 2.8GHz iMac. With its faster processor, the 24-inch, 2.8GHz iMac is expectedly faster than the 20-inch, 2.4GHz iMac on all of our application benchmarks--as well as many similarly priced Windows machines. Of particular note is the 2.8GHz iMac's performance on our multimedia multitasking test--perhaps our most punishing benchmark. The test performs simultaneous video and audio encoding, which typically taxes the resources of most systems. The 24-inch, 2.8GHz iMac's best-of-class performance on this test is an excellent indicator of the iMac's potential for tackling processor-intensive applications and juggling the demands of multiple applications concurrently vying for system resources.

The only performance area in which the iMac disappoints is with its 3D gaming proficiency--or lack of it. We were surprised to see the 24-inch turn in even lower scores on our Quake 4 test than we saw with the 20-inch model. This disparity is still a bit of a mystery for us as both systems use the same graphics engine. Regardless, while the bigger model nets you a larger screen, a faster processor, more memory, and bigger hard drive, there are no options for speedier graphics.

The ultimate question is whether the 24-inch, 2.8GHz iMac is worth spending $800 more than the 20-inch, 2.4GHz version for a 16 percent improvement in performance and 30 percent more screen real estate. Serious multitaskers and some prosumers can definitely gain additional screen area to support more open applications on the desktop, and the modest performance bump can make a difference during longer video or audio renders. Perhaps the ideal user is someone who needs as much processing power as possible from a Mac, but can't justify the much costlier Mac Pro.