How much faster is the "Unibody" MacBook compared to the "Early 2008 Penryn" MacBook Core 2 Duo?

Please note that all Macs mentioned in this Q&A have been discontinued. The "Late 2008/Unibody" MacBook was replaced by the "Mid-2009" 13-Inch MacBook Pro on June 8, 2009.

Quickly review a comparison of the "Late 2008/Unibody" MacBook models to the "Early 2008 Penryn" models that they replaced and it becomes readily apparent that the "Unibody" systems have improvements in design and architecture -- particularly for the graphics systems -- but have processors of similar speed.

The "Early 2008 Penryn" MacBook Core 2 Duo systems -- the MacBook "Core 2 Duo" 2.1 13" (White), 2.4 13" (White), and 2.4 13" (Black) -- have 2.1 GHz or 2.4 GHz Core 2 Duo processors and the "Late 2008/Unibody" MacBook models -- the MacBook "Core 2 Duo" 2.0 13" (Unibody) and MacBook "Core 2 Duo" 2.4 13" (Unibody) -- have 2.0 GHz or 2.4 GHz Core 2 Duo processors.

Architecturally, however, the "Late 2008/Unibody" models use a faster architecture with a faster system bus -- 1066 MHz up from 800 MHz -- faster memory -- 1066 MHz PC3-8500 DDR3 compared to 667 MHz PC2-5300 DDR2, and a faster graphics processor -- a 256 MB NVIDIA GeForce 9400M compared to a 144 MB Intel GMA X3100.

With similar processor speeds -- a bit slower on the low-end even -- and a modestly faster architecture, one should not expect a substantial overall performance boost except for tests involving graphics. For the precise difference, however, real-world testing is required.

The always reliable MacWorld ran Speedmark version 5 tests -- the publication's standard test suite -- and found that:

Comparing the top of line 2.4 GHz MacBook to its less expensive, lower-powered 2 GHz sibling, we find the high-end model nearly 9 percent faster in overall Speedmark performance, with narrower performance gaps in graphics tests and wider gaps in processor tests, like Cinema 4D.

Comparing the "Unibody" 2.0 GHz and 2.4 GHz models to the 2.1 GHz and 2.4 GHz models replaced, MacWorld found the new systems to be around 8 percent and 11.5 percent faster, respectively, including a graphics test.

For even more comprehensive testing, there is no better source than the superb AnandTech, which performed a number of real-world tests in iPhoto, Pages, and Quicktime and concluded:

With the exception of the Pages test, the numbers show very little difference between the old and new systems. The new 2.0 GHz MacBook is slower than the old 2.4 GHz model as you'd expect. . . I suspect the Pages test favors the new machines as it is a bit more disk-bound and the newer machines have faster drives. But if you want to know, the new notebooks aren't any faster in normal usage than the old ones.

Ultimately, the "Late 2008/Unibody" MacBook models are modestly faster than their predecessors -- just as one would expect from evaluating their respective specifications -- and provide reasonable performance with a sleek design at a modest price.

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