17- and 20-inch iMacs Core 2 Duo

Whenever Intel announces a new processor, it’s only a matter of time before that chip ends up in a Mac. Apple’s latest iMacs—two 17-inch models running at 1.83GHz and 2.0GHz, and the 20-inch model at 2.16GHz—are the first Apple hardware to take advantage of Intel’s Core 2 Duo processor.

With the new iMacs, Apple has filled out its all-in-one desktop line with four models (see our review of the new 24-inch iMac ) to fit almost every budget and desire for display size and features. However, performance gains from the new chips are modest compared with the previous Core Duo iMacs.

The models

The new crop of iMacs replace the $1,299 17-inch 1.83GHz Core Duo model and $1,699 20-inch 2.0GHz Core Duo model with two 17-inch versions and a 20-inch version (plus the 24-inch model). The new prices promise to appeal to a wide range of buyers.

The $999 17-inch 1.83GHz Core 2 Duo iMac—the first flat-panel iMac for less than $1,000—is a stripped-down model. It has the same 2MB of shared L2 cache as the previous iMacs, and is the only iMac model to ship without built-in Bluetooth 2.0 wireless networking, an Apple Remote, or a SuperDrive. It’s very similar to the iMac that Apple sells to educational institutions for $899, except that the extra $100 buys you a Core 2 Duo processor instead of Core Duo processor (running at the same speed) and a 160GB Serial ATA (SATA) hard drive instead of an 80GB hard drive. It includes 512MB of 667MHz RAM on two 256MB DIMMs, a 24x Combo drive, AirPort Extreme wireless networking, and Intel’s GMA 950 integrated graphics, which borrows the 64MB of RAM it uses from main memory, making a RAM upgrade a good idea on this model. You may want to spend the extra $75 to get 1GB of RAM (the maximum is 2GB).

The $1,199 17-inch 2.0GHz and $1,499 20-inch 2.16GHz models are nearly identical except for their different processor speeds, hard-drive capacities (160GB versus 250GB), and display sizes—their screens feature 1,440-by-900-pixel resolution and 1,680-by-1,050-pixel resolution, respectively. Both have 4MB of shared L2 cache, 8x double-layer SuperDrives, ATI Radeon X1600 graphics with 128MB GDDR3 memory, built-in AirPort Extreme and Bluetooth 2.0 wireless networking, and an Apple Remote. Both models also come with 1GB of 667MHz RAM, split between two 512MB SODIMMs.

It’s great that Apple has made 1GB of RAM the standard on these two models. Unfortunately, whereas matched pairs of RAM are essential for the $999 iMac—which improves graphics performance because of its integration with the system RAM—the other iMacs don’t gain anything from having two matched DIMMs instead of one (it does presumably save Apple money, however, as two smaller DIMMs are generally cheaper than one larger one). So upgrading RAM (up to the maximum of 3GB) requires removing one included DIMM to gain a free RAM slot—making it more expensive and wasteful to upgrade RAM on your own.

Each of the three models has a built-in iSight video camera, Gigabit Ethernet, an Apple Keyboard and Mighty Mouse, three USB 2.0 ports (plus two USB 1.1 ports on the keyboard), two FireWire 400 ports, built-in stereo speakers with 12-watts of digital amplification, a built-in microphone, and analog and digital audio input and output (the previous generation of iMac had analog-only audio input in addition to analog and digital audio output).

Performance

To see how well the new iMacs perform, the Macworld Lab put them through our standard suite of tests. All the new iMacs performed strongly and bested the previous top iMac—the 20-inch 2GHz Core Duo model—in most tests. The 17-inch Core 2 Duo iMac, running at the same processor speed as the old 20-inch model, scored 10 percent higher in our Speedmark suite, while the 20-inch 2.16GHz Core 2 Duo was 17 percent better—and both models cost hundreds of dollars less.

And although the 1.83GHz Core 2 Duo iMac clocked eight points behind the previous 2GHz iMac Speedmark score, it beat the older iMac in several tests: it posted a seven percent speed boost in Apple’s Compressor MPEG-2 encoding test and a 19 percent faster time in the iTunes MP3 encoding test.

The one area in which the 17-inch 1.83GHz iMac performed significantly worse was in our Unreal Tournament 2004 Frame Rate test. Because this model uses the Intel GMA 950 integrated graphics instead of dedicated high-speed graphics processing, the low-end Mac could process only 21.7 frames per second—60 percent fewer than the old iMac, and 67 percent to 73 percent fewer than the other new iMac models. The integrated graphics also caused noticeable differences in Nanosaur 2 (movement seemed less fluid), and opening and closing multiple Finder windows wasn’t nearly as smooth as with the other Core 2 Duo iMacs. However, the 1.83GHz model was able to play HD movie trailers without dropping frames. The other two models have much better frame rates of 65.5 (2.0GHz) and 74.4 (2.16GHz), which beat the old 20-inch iMac’s 54.1 frames handily—even though they all use the same ATI Radeon X1600 graphics processor with the same amount of RAM.

All three new iMacs were between nine percent and 24 percent faster than the old 20-inch iMac in our Adobe Photoshop CS2 suite of tests, which runs in Rosetta translation because Photoshop isn’t yet an Intel-native application. Even the low-end iMac shaved 14 seconds off the old model’s time of 2 minutes and 31 seconds.

In general, there was very little difference between the 2.0GHz and 2.16GHz models in terms of hands-on feel—both were snappy and responsive at most tasks. The $999 iMac, however, definitely suffered from its slower processor and lesser amount of RAM: launching apps took a little longer and applying transitions in iMovie was slow, for example. And the greater screen brightness of the 20-inch model was noticeable, but not a huge difference.

Macworld’s buying advice

The performance difference between the Core Duo and Core 2 Duo makes these upgrades basically speed bumps rather than completely new iMacs, but Apple does give you more Mac for less money. And now that Apple offers many iMac models, you have a better chance of finding one that precisely suits your needs and budget. If you want a low-cost iMac to have around the house for everyday use (with iLife and some higher-end apps), the 1.83GHz iMac is a nice system for the price (even factoring in a RAM upgrade from Apple). It also makes for an appealing system for many students, who can buy one for the same $899 price as the education iMac (   ).

But if gaming is your thing, or you plan to use graphics-intensive applications on a regular basis, you should spend the $200 more for the faster 17-inch model. If you’re looking for a bigger screen, the 20-inch model provides more than just additional pixels—it also gives you performance that is very similar to the 24-inch iMac (which, if you need the biggest, brightest screen and can justify spending the money, is a great choice).

[ Jonathan Seff is Macworld ’s senior news editor. ]

Editor’s note: This article was updated at 1:50 p.m. PT on September 18, 2006 to list the correct capacity of the 17-inch 2GHz iMac’s hard drive.