Benchmarks: Faster RAM, graphics boost iMac

Despite having a slightly slower processor than its predecessor, Apple’s new 17-inch 1.9GHz iMac G5 managed to keep pace with a 2.0GHz iMac G5, Macworld Lab testing has found. Credit for the new iMac’s strong showing goes to the other under-the-hood improvements, including faster RAM and higher-performance graphics.

Apple updated its iMac line earlier this month, introducing the 17-inch, 1.9GHz model along with a 20-inch 2.1GHz machine. Both new desktops are the first iMacs to ship with DDR2 RAM, a faster type of memory than what previously came installed in iMac models. The refurbished iMacs also became the first Macintosh models to feature PCI Express graphics, a growing standard on the PC side. PCI Express provides faster performance for graphics systems than the AGP interface on previous Mac-compatible graphics cards.

Those improvements kept the 1.9GHz iMac G5 within a second or two of the formerly top-of-the-line iMac, despite that model’s nominally faster 2.0GHz PowerPC G5 processor. (Our tests did not include the new 2.1GHz iMac G5, which is not yet widely available.)

17-inch 1.9GHz iMac Tested

Speedmark 4 Adobe Photoshop CS2 Cinema 4D XL 9.1 Compressor 2.0 iMovie HD iTunes 6.0.1 Unreal Tournament 2004
OVERALL SCORE SUITE RENDER MPEG2 ENCODE RENDER MP3 ENCODE FRAME RATE
17-inch iMac G5/1.9GHz 178 1:23 2:53 12:49 0:32 1:42 35.4
20-inch iMac G5/2GHz 178 1:24 2:44 12:50 0:33 1:39 32.2
Power Mac G5/2GHz dual-core 208 1:04 1:23 6:20 0:36 0:58 40.6
>Better <Better <Better <Better <Better <Better >Better

Best results in bold. Reference systems in italics .

Speedmark 4 scores are relative to those of a 1.25GHz Mac mini, which is assigned a score of 100. Adobe Photoshop, Cinema 4D XL, iMovie, and iTunes scores are in minutes:seconds. All systems were running Mac OS X 10.4.2 with 512MB of RAM, with processor performance set to Highest in the Energy Saver preference pane. 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. 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. To compare Speedmark 4 scores for various Mac systems, visit our Apple Hardware Guide .—Macworld Lab testing by James Galbraith and Jerry Jung

The new 1.9GHz iMac topped the older 2.0GHz model in four of our seven tests; the older desktop came out on top in two tests, with both iMacs recording matching Speedmark scores. Of particular interest was the Unreal Tournament 2004 test, in which the 1.9GHz model’s PCI express card was able to push 10 percent more frames per second than the 2.0GHz iMac.

For comparison’s sake, we included a new dual-core 2GHz Power Mac G5 to see how Apple’s consumer and pro desktops fared against one another. Not surprisingly, the dual-core machine fared better in most tests, indication that certain applications really take advantage of two processing units on a single chip. Using Compressor and Cinema 4D XL, the Power Mac took almost exactly half the time to complete the tasks when compared to the single-core, single-chip iMacs. Other applications, particularly iMovie HD, gained almost nothing from the second processing core.

Macworld will soon have a full review of the new iMacs, including benchmark results for the 20-inch 2.1GHz iMac G5.

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