Improve Diablo 3 Performance in Mac OS X

Diablo 3 system requirements are fairly lenient but as many Mac users have discovered, performance on some computers just isn’t that great. Even some of the newest Macs with the best GPU’s are experiencing performance issues. The good news is that Blizzard is on the case and actively working on patches to address many of these graphics issues in Mac OS X, but nobody is quite sure when that patch will be released. Until then, here are some optimization tips to improve the games playability in OS X.

Check the Frame Rate (FPS) in Diablo 3

First things first, let’s check the FPS (frames per second) of Diablo 3. This is the easiest way to benchmark how various changes effect game performance:

In gameplay (not the character selection, menu, or loading screens, etc) hit Control+R to show the FPS in the upper left corner

Control+R works in both Mac OS X and Windows if you feel like comparing performance between the two OS’s. You will have to hit Control+R to show frame rate each time you are in game play, keep this in mind while you adjust settings.

General Performance Optimization Tips for Diablo 3 in Mac OS X

Here are some general optimization tips, if the game is running horribly try them all. If it’s running reasonably well, tweak the settings as appropriate until you can get a stable frame rate with decent graphics.

Quit All Other Applications – Background processes aren’t going to help you, quit every other app before starting the Diablo III client for the best performance.

Set the Maximum Frame Rate to 40 – this helps with FPS consistency, preventing those stutters you can experience when moving from walking around and suddenly into a complex battle sequence. Keep the background frame rate low as well.

Disable Anti-Aliasing – anti-aliasing looks great but disabling it can add a constant 3-8 FPS

Turn all settings to “Low” – this seems obvious but not everyone does it, setting everything to low makes a big difference

Disable Shadows – turning off shadows gives you an instant jump in frame rate

Run at a Lower Resolution – Choosing a lower screen resolution for the game will likely have the biggest performance impact, though it also can dramatically effect how the games graphics look. Pick as low a setting as you can tolerate graphically.

Run in Windowed Mode – Once this is set you can drag the window by the corner to resize the windowed screen. This has basically the same effect at running D3 a lower resolution, but because it’s contained in a smaller window the graphics won’t look as pixelated.

Turn Off Secondary Displays – If you’re using a dual-screen setup with a laptop or otherwise, disable the primary screen or only use the primary screen. You can do this with a technical approach, or the lazy way by turning down brightness to zero and setting the external display to the primary screen. This causes the GPU to use less resources to drive two screens, freeing those resources for the game instead.

You may want to take a glance at Blizzards general recommendations and troubleshooting tips too.

Advanced Tweak: Disabling Trilinear Filtering

Disabling trilinear filtering can have a huge impact on game performance, but oddly this isn’t included in the general Graphics settings so we’ll have to dig around in the filesystem to do it:

Quit Diablo 3

From the OS X desktop, hit Command+Shift+G and enter the following path:

~/Library/Application Support/Blizzard/Diablo III/

Find and locate the “D3Prefs.txt” file, and open it in TextEdit

Hit Command+F and search for “DisableTrilinearFiltering”, change the setting from “0″ to “1″

Save the file and exit out of TextEdit

Relaunch Diablo 3, start a game, and hit Control+R to see the FPS difference

Turning off trilinear filtering makes the game look a little more fuzzy, but for many users the boost in frame rate is worth it.

As you can see you’ll have to experiment with various settings to see what works best for you, but with a combination of the above tips you should be able to boost frame rate easily 10-25FPS while still maintaining tolerable graphics settings.

Last Straw: Play in Windows with Boot Camp

This may not be a popular recommendation, but if possible, you should install Diablo 3 in Windows and run the game from Boot Camp instead. Performance will be dramatically improved on virtually all Mac hardware if the game is run in Windows because of better optimizations, DirectX, and better graphic driver support. If you have a spare Windows key laying around and the hard disk space to support a Windows installation, this is really the best bet.

One final tip regardless of running in OS X or Windows: wait for every patch to download and install before playing the game. Sometime in the near future Blizzard will be releasing patches that directly address the graphical issues that users are experiencing, you don’t want to miss the patch just because you are anxious to play.