There appears to be no performance penalty for using dual-core processors instead of two single-core processors with the same clock speed, Macworld Lab has concluded after preliminary testing of the dual-core Power Mac G5s released by Apple a week ago.
The latest Power Macs ship with dual-core 2.0GHz and 2.3GHz PowerPC G5 processors, as opposed to the two single-core chips in the preceding models. Apple also added faster DDR2 RAM and PCI Express graphics cards to the new models, replacing DDR memory and AGP graphics cards. That change helped the new Power Macs edge past their respective predecessors with similar clock speeds.
The dual-core 2.3GHz Power Mac fared better than a single-core dual-processor 2.3GHz model in six of our seven tests. In the seventh—MP3 encoding in iTunes 6—the dual-core and single-core 2.3GHz Power Macs turned in matching times.
Our tests didn’t include the Power Mac G5 Quad, which comes with two dual-core 2.5GHz G5 processors. That model isn’t shipping yet.
Dual-Core Power Mac G5 Benchmarks
|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|
|Power Mac G5/2GHz dual-core||208||1:04||1:23||6:20||0:36||0:58||40.6|
|Power Mac G5/2.3GHz dual-core||226||0:56||1:11||5:35||0:33||0:52||50.1|
|Power Mac G5/2.3GHz dual-processor||224||0:59||1:13||6:03||0:36||0:52||40.2|
|Power Mac G5/2.7GHz dual-processor||248||0:52||1:03||5:12||0:25||0:46||47.7|
Best results in bold. Reference systems in italics .
While the two dual-core systems compare favorably to single-core Power Macs with similar clock speeds, neither new model could overcome the gap in speed to give the dual-processor 2.7GHz Power Mac G5 any real competition. The one exception turned out to be in our Unreal Tournament 2004 tests, where the dual-core 2.3GHz machine’s PCI Express graphics card squeezed out a couple more frames per second than the dual-processor 2.7GHz G5 did; the dual-core Power Mac produced ten more frames per second than a dual-processor 2.3GHz Power Mac.
The lack of a noticeable performance penalty for dual-core chips bodes well for the Power Mac G5 Quad, once it becomes available for testing. With its pair of dual-core processors, it figures to be the fastest Mac desktop ever.
This story, "Power Mac G5 Benchmarks: Dual-core's strong showing" was originally published by PCWorld.