You would expect an iMac powered by the fastest Core 2 Duo chip available to outperform iMacs with lesser clock speeds. And that was certainly the case when we ran our benchmark testing on Apple’s build-to-order iMac Core 2 Duo with a 2.33GHz processor—it easily beat its fellow Core 2 Duo models as well as an older Intel-based iMac running on a 2GHz Core Duo chip.
But what you might not expect is for that high-end consumer machine to beat out a professional tower powered by two dual-core chips in Macworld Lab tests. Nevertheless, that’s exactly what happened—the 2.33GHz iMac Core 2 Duo edged past the 2GHz Mac Pro. Granted, that’s not the standard Mac Pro configuration —that model comes with two 2.66GHz processors—but it’s still impressive to see a dual-core consumer machine outperform a quad-core desktop aimed at professionals.
As mentioned in our first round of iMac tests, we received the recently updated iMac Core 2 Duo line in stages. Our initial tests covered the 17-inch, 2GHz iMac and the 20-inch, 2.16GHz model. This time around, we’re concentrating on the 24-inch iMacs—an off-the-shelf model that ships with a 2.16GHz Intel Core 2 Duo processor, a 250GB hard drive, and an NVIDIA GeForce 7300GT graphics card with 128MB of memory, and a second built-to-order configuration featuring a 2.33GHz Core 2 Duo processor, NVIDIA GeForce 7600 GT graphics card with 256MB of memory, and twice the hard drive capacity of the standard 24-inch iMac.
With a Speedmark score of 259, the beefed up iMac (with 8 percent faster processing cores) was 6 percent faster than the standard configuration 24-inch iMac. More impressive, it was about 2 percent faster than the quad-core 2GHz Mac Pro in Macworld ’s overall system performance benchmark. Granted, the clock speed of the optional Core 2 Duo is considerably faster than the Xeon, but doing the math: the iMac’s 4.6GHz of processing power versus the 8GHz of processing power on the Mac Pro, gives the Mac Pro with a 74-percent theoretical speed advantage. The tests do not indicate that the higher-end desktop is always exploiting that advantage.
Core 2 Duo iMac Benchmarks
| Speedmark 4.5 | Adobe Photoshop CS2 | Cinema 4D XL 9.5.21 | Compressor 2.1 | iMovie 6.0.2 | iTunes 6.0.4 | Unreal Tournament 2004 | Finder | |
|---|---|---|---|---|---|---|---|---|
| OVERALL SCORE | SUITE | RENDER | MPEG2 Encode | AGED EFFECT | MP3 ENCODE | FRAME RATE 1024 x768 | ZIP ARCHIVE | |
| 24-inch iMac Core 2 Duo/2.33GHz* | 259 | 1:47 | 0:57 | 2:12 | 0:48 | 0:56 | 83.6 | 2:15 |
| 24-inch iMac Core 2 Duo/2.16GHz | 245 | 1:55 | 1:01 | 2:25 | 0:51 | 1:06 | 79.3 | 2:22 |
| 20-inch iMac Core 2 Duo/2.16GHz | 245 | 1:55 | 1:01 | 2:37 | 0:52 | 1:03 | 74.4 | 2:22 |
| 17-inch iMac Core 2 Duo/2GHz | 232 | 2:04 | 1:06 | 2:50 | 0:57 | 1:03 | 65.5 | 2:34 |
| 17-inch iMac Core 2 Duo/1.83GHz | 202 | 2:17 | 1:13 | 3:07 | 1:02 | 1:10 | 21.7 | 2:46 |
| 20-inch iMac Core Duo/2GHz | 210 | 2:31 | 1:11 | 3:21 | 1:03 | 1:26 | 54.1 | 2:34 |
| Mac Pro/2GHz | 254 | 1:50 | 0:37 | 1:57 | 0:48 | 0:59 | 73.4 | 2:32 |
| >Better | <Better | <Better | <Better | <Better | <Better | >Better | <Better |
Best results in bold. Reference system in italics . * denotes build-to-order model with upgraded video card
Speedmark 4.5 scores are relative to those of a 1.25GHz Mac mini, which is assigned a score of 100. Adobe Photoshop, Cinema 4D XL, iMovie, iTunes, and Finder scores are in minutes:seconds. All systems were running Mac OS X 10.4.7 with 1GB of RAM, with processor performance set to Highest in the Energy Saver preference pane when applicable. The Photoshop Suite test is a set of 14 scripted tasks using a 50MB file. Photoshop’s memory was set to 70 percent and History was set to Minimum. We recorded how long it took to render a scene in Cinema 4D XL. We used Compressor to encode a 6minute:26second DV file using the DVD: Fastest Encode 120 minutes – 4:3 setting. In iMovie, we applied the Aged video effect to a 1-minute movie. We converted 45 minutes of AAC audio files to MP3 using iTunes’ High Quality setting. We used Unreal Tournament 2004’s Antalus Botmatch average-frames-per-second score; we tested at a resolution of 1,024-by-768 pixels at the Maximum setting with both audio and graphics enabled. We created a Zip archive in the Finder from a 1GB folder.—Macworld Lab testing by James Galbraith and Jerry Jung
As usual, the applications most adept at using multiple processors favored the quad-core Mac Pro. Our Cinema4D render test showed the low-end Mac Pro finishing the task 35 percent faster than the build-to-order iMac. Our Aperture tests results, broken out below, show the Mac Pro to be 30 percent faster exporting RAW files as JPEGs, and our Compressor MPEG2 encoding test shows the quad-core system beating this fastest iMac by 35 percent.
Aperture and Unreal Tournament Tests
| Unreal Tournament 2004 | Aperture | |
|---|---|---|
| FRAME RATE 1680 x1050 | Export JPEG | |
| 24-inch iMac Core 2 Duo/2.33GHz* | 77.7 | 1:24 |
| 24-inch iMac Core 2 Duo/2.16GHz | 58.9 | 1:29 |
| 20-inch iMac Core 2 Duo/2.16GHz | 55.8 | 1:29 |
| Mac Pro/2GHz | 50.6 | 1:07 |
| >Better | <Better |
Best results in bold. Reference system in italics . * denotes build-to-order model with upgraded video card
All systems were running Mac OS X 10.4.7 with 1GB of RAM. We used Unreal Tournament 2004’s Antalus Botmatch average-frames-per-second score; we tested at a resolution of 1,680-by-1,050 pixels at the Maximum setting with both audio and graphics enabled. We recorded the time it took to import 30 RAW files into Aperture and then export them as JPEGs.—Macworld Lab testing by James Galbraith and Jerry Jung
But these tests are in the minority. Many applications, like iMovie, iTunes, Photoshop, and Microsoft Office—not to mention tasks most folks spend the day running on their Macs, like word processing, spreadsheets, Web browsing, and 3-D games—are either not as CPU-intensive or are less savvy when it comes to multiprocessing. Thus, the iMac Core 2 Duo’s faster clock speed trumps the multiple Xeons found in the 2GHz Mac Pro.
The custom iMac also included higher-end graphics card than the standard 24-inch model, a $125 option that doubles the amount of graphics memory and moves from an NVIDIA GeForce 7300GT to a GeForce 7600GT. When running Unreal Tournament at 1,024-by-768 resolution, the number of frames the custom system was able to display was greater than the standard iMac, but not stunning. Boosting the resolution to the native full resolution of the 20-inch iMacs (1,680-by-1,050 pixels) showed the benefit of using the faster, more memory-laden card. The standard configuration’s frame rate dropped by 20 frames per second at the higher resolution, the custom iMac slowed down by only 6 frames per second.
We’ll have reviews of the entire iMac Core 2 Duo line in the coming days.
[ James Galbraith is Macworld Lab director. ]
Editor’s note: This article was reposted at 3:10 p.m. PT to clarify a comparison between the iMac Core 2 Duo and Mac Pro and to correct a typo about the Mac Pro’s processor. Neither of these changes affected the results or conclusions of Macworld Lab’s tests.