Review: Intel Core Duo iMac

Apple likes to be the magician that whips the tablecloth off the table while leaving dishes, a vase with a rose, and silverware in place. They've exchanged major portions of the hardware and operating system architecture multiple times with pain at each transition.

This time, Apple is swapping processors, leaving its long-time partners Motorola-cum-Freescale and IBM behind with the jointly developed PowerPC chips that have powered Macs for a decade.

Months ago, Apple declared it would move to Intel’s latest number crunchers, and at Macworld Expo in early January, the company announced it had its first models ready to go.

The iMac is the first off the block, shipping now. A new laptop line, called the MacBook Pro, will appear in February. Both computers use the Intel Core Duo, which is a single chip that contains two processors known as cores. The chip uses significantly less energy than the PowerPC chips they replace. Apple claims raw calculation improvements of 2- to 3-fold for the iMac and 4- to 5-fold for the MacBook Pro.

Because IBM was unable to deliver its most advanced G5 chips in a form that wouldn’t produce far too much heat in laptops, Apple was compelled to migrate to new chips. It made little sense for the company to support multiple system architectures, and thus the move to Intel was inevitable.

It’s easy for Apple to top its previous PowerBook performance because they were using last generation PowerPC chips. But it’s a little harder on the iMac side, where G5s were already delivering a boost.

The iMac looks exactly like its PowerPC-based predecessor. The specs are slightly different, but the functions are not. This iMac comes in 17-inch and 20-inch varieties; I tested the 20-inch model. It supports a second display using DVI or VGA for extended video, which is a new feature for the product line. It omits a modem -- a separate $49 part -- but includes Bluetooth 2.0+EDR, Wi-Fi, and 10/10/1000 Mbps Ethernet. It also has FireWire (IEEE 1394) at 400 Mbps and USB 2.0 support.

The iMac comes bundled with the iLife ’06 suite of digital media applications, Apple's Safari browser and Mail program, and a host of other utility software. Apple said all this software is now built as universal applications that run native on both PowerPC and Intel chips by containing the programming code for both. The operating system is native based on the platform it's installed on. The key measure of this new system is not whether it performs enormously faster than its predecessor that used a PowerPC, but rather whether it works well. Without carrying out the benchmarks that magazine testing laboratories are known for -- and which are starting to appear -- it’s still clear from the moment the system is booted and programs are launched that this iMac is zippier.

Because most programs written for Mac OS X aren’t yet revised to run natively using Intel code, Apple included a seamless emulation system called Rosetta that interprets PowerPC code and converts it on the fly to Intel instructions. Apple has said that Rosetta works flawlessly for the vast majority of software, and in my testing of a few dozen popular third-party Macintosh programs, I was unable to cause a crash or significant performance problems in normal operation.

The most obvious of these packages is Office 2004 for Mac, the latest version of the venerable productivity suite. Word, Excel, PowerPoint, and Entourage work fine via Rosetta, and Microsoft has promised minor updates by March that would take care of any minor compatibility or performance issues. They have committed to a fully native version of Office for Mac, but no delivery date has been set.

Adobe programs such as Photoshop also work through Rosetta, although much slower than on a native system. It’s usable, but doesn’t have the zip of Apple’s iLife packages. Early benchmarks published by a variety of sources online put the speed of many programs run via Rosetta at 50 percent of their PowerPC performance, while programs that are universal run at par or up to 50 percent faster.

However, that’s when either non-native or universal programs are performing computationally intensive tasks, like resizing an image or repaginating long documents. For routine interactive use, the speed hit or improvement isn’t noticeable.

There is a category of software that won’t run at all via Rosetta: programs that depend on advanced graphics and processor features found in the PowerPC G4 and G5 chip, primarily the Altivec system that accelerates certain kind of calculations often used in image, video, and audio processing. Apple told me in a briefing at Macworld Expo that Final Cut Pro, for example, will simply not operate on an Intel-bearing machine. Apple’s pro applications are due out in universal versions in March.

The first Intel iMac is a success in that it can barely be distinguished from its predecessor. Future models will be judged more harshly on performance, but there’s a lot of room to grow with Intel Core Duo roadmap.