How much faster are the custom configured original Mac Pro models with either 3.0 GHz "Quad Core" or 3.0 GHz "Eight Core" processors compared to the stock Mac Pro? How much slower is the custom configured Mac Pro with 2.0 GHz "Quad Core" processors?

Please note that all systems mentioned in this Q&A have been discontinued. The original Mac Pro models were replaced on January 8, 2008 by the "Early 2008" Mac Pro models.

Although it might be tempting to assume that with 13% faster processors than the stock Mac Pro Quad 2.66, the Mac Pro configured with two 3.0 GHz Dual Core Xeon 5160 processors would be 13% faster, and with 25% slower processors, the Mac Pro configured with two 2.0 GHz Dual Core Xeon processors would be slower than the stock configuration by a similar margin.

Likewise, with twice as many cores, it would be tempting to assume that the Mac Pro configured with two 3.0 GHz Quad Core Xeon X5365 processors would be twice as fast as the model with two 3.0 GHz Dual Core Xeon 5160 processors.

However, as all of the original Mac Pro models share identical motherboard designs, memory, PCI architectures, hard drives, and default graphics cards, the performance difference between models tends to be more modest when the systems are configured identically as well.

In a "First Look" the always reliable MacWorld compared the original "upgraded" 3.0 GHz "Quad Core" model and the "downgraded" 2.0 GHz "Quad Core" Mac Pro to the stock Mac Pro Quad 2.66, as well as the Power Macintosh G5 Quad 2.5, Power Macintosh G5/2.7 DP and iMac "Core Duo" 2.0 20-Inch. All systems were configured with 1 GB of RAM.

The entire piece should be read for the full perspective provided by the author, but regarding the faster system, MacWorld noted that "the 3 GHz machine posted a score of 313, setting a new standard for our system performance test suite" and concluded that "the 3 GHz machine posted an improvement over the 2.66 GHz Mac Pro of about 5 to 6 percent on most tests" and "beat the 2.66 GHz model in all tests, but usually just by a few seconds." Regarding the 2.0 GHz Mac Pro compared to the 2.66 GHz model, MacWorld concluded that the "downgraded" model was roughly "15 percent" slower.

The always excellent BareFeats also tested the original "upgraded" Mac Pro Quad 3.0, but loaded it with 3 GB of memory to take full advantage of the 256-bit wide memory architecture. The complete analysis should be read in its entirety, but the difference when configured with more RAM is impressive. BareFeats noted that the Mac Pro Quad 3.0 with 3 GB of RAM was only "5% slower" than a Power Macintosh G5 Quad 2.5 with 1 GB of RAM running Photoshop CS2 and as much as "85% faster" in a series of Universal application tests.

BareFeats quickly got their hands on the "Eight Core" Mac Pro as well -- introduced April 4, 2007 and configured with two 3.0 GHz "Quad Core" Xeon X5365 processors -- and found that the "Eight Core" model was "45% faster" in CineBench tests and "56% faster" in Geekbench tests than the 3.0 GHz "Quad Core" model. In real-world Photoshop CS3 tests, however, the systems were nearly identical. For in-depth testing and analysis regarding this performance gap, be sure to read the full piece.

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