Diablo 3 Slow on Mac? Here is a Solution Against Low FPS

Stay a while and listen! Like many other users, I have suffered from unplayable FPS on my Mac. Although Blizzard has accepted the problem and promised to publish a patch in the upcoming weeks, they seem to be busy with the recent hack incident. Therefore, I decided to publish a temporary solution.

The trick is to find the D3PREFS.TXT file, which contains some settings which are unavailable in the normal user interface. This file is hidden in /users/[YOUR_USERNAME]/Library/Application Support/Blizzard/Diablo III . Easiest way to access this folder is to open Finder and click Go –> Go To Folder… . There, you can enter /users/[YOUR_USERNAME]/Library and start browsing from there.

What you have to do is to open & edit this file manually. Here are the settings I made to increase my FPS to a playable degree. Some of those settings might also be setup through the user interface, but not all:

  • DisplayModeWindowMode “1”
  • DisplayModeUIOptWidth “800”
  • DisplayModeUIOptHeight “600”
  • DisplayModeWidth “896”
  • DisplayModeHeight “656”
  • DisplayModeRefreshRate “60”
  • DisplayModeBitDepth “32”
  • ShadowQuality “0”
  • PhysicsQuality “0”
  • ClutterQuality “0”
  • Vsync “0”
  • Letterbox “0”
  • Antialiasing “0”
  • LowFX “1”
  • LimitForegroundFPS “1”
  • MaxForegroundFPS “25”
  • LimitBackgroundFPS “1”
  • MaxBackgroundFPS “1”
  • DisableTrilinearFiltering “1”
  • ColorCorrection “0”
  • ReflectionQuality “0”
  • HardwareClass “1”
  • ChannelsToUse “16”
  • ReverseSpeakers “0”

After doing this setup and restarting the game, my FPS increased from 5-10 to around 20, which made the game at least playable.

Alternatively; if you want to play in a readable full-screen mode so that you can read things on the screen, you can try the following configuration enduring a cost of 2-3 FPS:

  • DisplayModeFlags “8”
  • DisplayModeWindowMode “0”
  • DisplayModeWinLeft “552”
  • DisplayModeWinTop “482”
  • DisplayModeWinWidth “800”
  • DisplayModeWinHeight “600”
  • DisplayModeUIOptWidth “832”
  • DisplayModeUIOptHeight “624”
  • DisplayModeWidth “832”
  • DisplayModeHeight “624”
  • DisplayModeRefreshRate “60”
  • DisplayModeBitDepth “32”
  • MipOffset “1”
  • ShadowQuality “0”
  • PhysicsQuality “0”
  • ClutterQuality “0”
  • Vsync “0”
  • Letterbox “0”
  • Antialiasing “0”
  • LowFX “1”
  • LimitForegroundFPS “0”
  • MaxForegroundFPS “27”
  • LimitBackgroundFPS “1”
  • MaxBackgroundFPS “1”
  • DisableTrilinearFiltering “1”
  • ReflectionQuality “0”
  • ChannelsToUse “32”
  • ReverseSpeakers “0”

I have also heard that Bootcamping into Windows made also a difference of 5 FPS, and that playing on the built-in laptop screen (instead of an external display) helps as well. But the solution above was good enough for me while I wait for Blizzard’s official fix.

Here is the totally useless Blizzard post to improve Mac performance; I think they released it to buy some time: http://us.battle.net/support/en/article/diablo-iii-running-slow-or-choppy-mac .

Here are the specs of my Mac:

  •   Model Name: MacBook Pro
  •   Model Identifier: MacBookPro5,4
  •   Processor Name: Intel Core 2 Duo
  •   Processor Speed: 2,53 GHz
  •   Number of Processors: 1
  •   Total Number of Cores: 2
  •   L2 Cache: 3 MB
  •   Memory: 8 GB
  •   Bus Speed: 1,07 GHz
  • Chipset Model: NVIDIA GeForce 9400M
  •   Type: GPU
  •   Bus: PCI
  •   VRAM (Total): 256 MB

9 thoughts on “Diablo 3 Slow on Mac? Here is a Solution Against Low FPS

  1. When the new patch comes out will I have to go back and edit these settings again? Thanks in advance for the help!

    • Yes, I would suggest so. Depending on the quality of Blizzard’s upcoming patch, I might attempt tweaking the file again if I need to. But I would keep the initial version of the file initially.

    • I have Mac OS X Lion and this folder is approved to exist by other users too. If you have Lion as well, make sure that you search the folder through the Finder menu Go -> Go To Folder; it can’t be browsed through usual Finder windows. Otherwise, you have to search the file elsewhere. I can’t tell where, but D3PREFS.TXT must exist somewhere; otherwise the game wouldn’t run😉

  2. oh man. since some day i realized the game is slow, even though i set up the options, the setting has changed in the file. I guess the auto launcher makes it. any solutions?

    • After patch 1.0.2b, Blizzard fixed the Mac performance problem. You shouldn’t be experiencing any difficulties now – even without file modification.

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