Wrapping up the iMac benchmarks

Comparing the performance of the iMac Core Duo to PowerPC-based Macs proved to be quite a challenge for us here at Macworld Lab. With so few Universal-binary applications available at the time of the Intel-based iMac’s release, our performance evaluation relied heavily upon the recently announced, though buggy, iLife ’06.

As the April 2006 issue went to press, Apple released updates to several applications in the iLife ’06 suite. And though the updates were welcome, it sent us scrambling to update the iMac Core Duo review as the issue was being shipped.

It turns out that the assorted iLife updates did fix a few bugs, but changed little in terms of performance. In fact, there were no differences in our tests of iPhoto, iTunes, or four of our five iMovie tests. The only task that changed was the iMovie Export to Web result. The trials with the updated software ran about 45 percent faster on the Intel-based iMacs, and about 23 percent slower running on the PowerPC iMac—though not enough for the Intel Macs to overtake the PowerPC reference system.

Upon closer examination, we discovered the reason for these speed differences—the preset for Export to QuicktTime/Web had been changed radically. If you choose this preset in iMovie HD 6, you’ll get a 12.5MB, 240×180 pixel QuickTime movie, using QDesign Music 2 and H.263 codecs. If you choose this preset in iMovie HD 6.0.1 you’ll get a 9.6MB, 320×240 pixel QuickTime movie using AAC and H.264 codecs.

Using the expert settings in the Share menu, we were able to closely match version 6’s settings in 6.0.1 and found the results for the Intel iMacs were roughly back in line with the original results we printed.