Upgrading Memory
in your MacBook

"To Pair or Not to Pair"

Since day one, Apple has strongly recommended that memory going into models with the Intel GMA950 Video chipset be installed in pairs. GMA950 video equipped Macs do not have dedicated Video Memory for display and rather the GMA950 actually shares 64MB from your main system memory installed.

As all of the Intel Core 2 Duo Macs (same is true between Core Duo Macs) share the same memory controller and processor. It is only on the GMA950 equipped models, which have the shared memory use for video, that are pushed to have only matched pairs of memory installed - for enabling the 128MBit memory addressing. In the Apple store, you'll find that while the current Core 2 Duo models with Nvidia or ATI video offer memory options on non-pairs - the GMA950 equipped model configs offer memory options that only include pairs.

Despite Apple's strongest recommendations for memory pairing, the test results we have from the current Apple MacBook 1.83GHz 13.3" Core 2 Duo laptop cause us to recommend otherwise. When the iMac G5 came out, paired memory for performance interleaving was an option there as well - but testing showed that you were better off upgrading to have more memory via replacing one module than buying less memory so the budget could support two modules. We really believed that it would be different with these GMA950 video equipped Intel Macs because of them sharing the system memory - something that wasn't a factor with the iMac G5. The bottom line is that it's not at all what we expected.

Apple MacBook Memory Testing of 512MB, 768MB,1.0GB, 1.25GB, 1.5GB, 2.0GB and 3.0GB configurations by Other World Computing.

XBench Results

XBench is a standardized utility for measuring the performance of your computer, as compared to a "baseline" computer. (More information and the application, itself, can be found here.)

For this test, we checked all the options except for the Disk Test, as it was the only one that did did not either touch System memory or Video Memory. Higher Point results are better.

Cinebench Results

This utility is supposed to tell you how well the 3D Modeling application 'Cinema 4D' will perform on your system. It's considered a good test of processor and overall video performance. It is cross-platform and can be found here.

These results come from adding up the "score" for each of the individual tests performed in its full test suite. Higher point results are better.

Photoshop Results

Adobe Photoshop is a failrly resource-intensive program which is currently not Intel native. This test, therefore also tests the RAM requirements of Rosetta, as well as those of Photoshop itself.

This test measures the time (in seconds) it takes to execute a custom 21-step action script using Adobe Photoshop CS. Lower times are better.

After Effects Results

Adobe After Effects is a failrly resource-intensive program which is currently not Intel native. This test, therefore also tests the RAM requirements of Rosetta, as well as those of After Effects itself.

This test measures the time (in seconds) it takes to Render 10 frames in Adobe After Effects Pro 6. Lower times are better.

"Stress Test" Results

This test also times how long it takes Adobe Photoshop to run a series of 21 actions. However, in addition to Photoshop, the iTunes Visualizer is also set to run. This generally taxes both the video card and the processor. Lower times are better.

Halo Results

In order to heavily tax the video card, we ran the time demo of the Intel-native version of the popular game, Halo.

Results are the average frame rate (in frames per second) achieved. Higher results are better.

In conclusion

More memory is overall better than having less memory that is interleaved. There is a huge benefit to upgrading even just to 768MB (replacing a one of the 256MB with a 512MB) from a factory 512MB config. General performance is better having more 1.25GB or 1.5GB by replacing one of the stock modules with a 1.0GB Memory Module vs. buying two 512MB modules for about the same cost and only having 1.0GB total. Of course, you'd be even better off with 2GB or 3GB, but even 1.25GB or 1.5GB should give you the performance you need.