Grim Dawn Optimization Guide

Various games have heavy performance issues with the default windows timer resolution set to 15ms. Crysis 3 and a few others I've found work better with this fix.

Note that settings the timer resolution to 1ms will increase pc power consumption by around 0.3w. This will affect Laptop battery life if you're a portable user.

Go to and download the "Update: Cyberdyne`s updated pack" at the bottom of the first post:
Once downloaded, extract the folder and run Installer.bat
At the installer, press 4 and hit Enter to install the C package of timer resolution.
Once installed, at the main screen press 6 to start the resolution service, then exit the installer and you're done - the timer resolution will now be an automatic background service.

I've personally patched the Grim Dawn.exe with the NTCore 4GB Patcher without any issues. You can view more information / download it here: http://www.ntcore.com/4gb_patch.php

Originally posted by NTCore:

This very little tool patches x86 executables in order to let them have 4GB (instead of only 2) of virtual memory on x64 platforms.

To use: place the patcher in your grim dawn directory, run the patcher, browse to your Grim Dawn.exe and patch away. A backup will be made and you can also re-verify game files in the steam-game options to go back to stock.

Windows may be parking some of your CPU cores.
Go to and download: Extract the folder and run the unpark application. Inside you can ensure you're CPU's are all unparked and set to maximum power.
source: http://coderbag.com/Programming-C/CPU-core-parking-manager

Optimizing system.ini
First we will ensure the security permissions are correct so that the following tweak is accessible by our user account.

Go to C:\Windows folder and search for the system.ini file. Once found, right click it, select properties, click the Securtiy tab, then under Groups or user names click Edit.
In this new Security window select the Users profile in the list (it will have your windows account username in parathesis / brackets), once selected tick all the Allow boxes in the Permissions for Users section and then click Apply and Ok, and exit the system properties window, but stay at the file for the next step!

Now let's improve windows memory management, especially for 16bit file streams.
Open system.ini (in notepad if confused) and replace the exisitng data with the following, then save and exit:

If you need to quickly access the system.ini file:
Hold down your windows key and press R (Windows + R) to show the run window.

On the run screen input "system.ini" without quotes and press enter. A notepad file will open. You can also search for system.ini via Start>Search>"system.ini"

Permissions all-around
Ensure admin access is enabled for both Steam.exe and Grim Dawn.exe:

Disable Steam overlay
Steam overlay has been known to cause instability and FPS loss in various games.
In steam right click Grim Dawn in your library list and go to Properties, untick the box that enabled Steam overlay. Stay in the launcher options for the next step...

Force all cores on application
In steam right click Grim Dawn in your library list and go to Properties. Click set Launch Options and in the window add . Click Ok.

AMD CPU players
Many games I've played that struggled on my AMD 6300 FX Machine were sometimes helped by adjusting certain bios settings. Accessing your bios is usually done by pressing f2/f5/f8/f12/del when you first boot your computer. Sometimes the bootscreen will display the key required to access the bios.
Once inside your bios : Disable :
(some of these options may not be visible/available; simply disable what you have.)

You may also want to try enabling/disabling HPC (High Performance Computing) mode. *May also appear as High Precision Event Timer.

My AMD PC i have that is running GD fine at the moment:
AMD FX 6300 @ 4.8GHz
8GB RAM
AMD 7950 3GB
output to 2560x1440 resolution (1440p)

Hopefully that gives you some ballpark to aim for. I built my AMD system for the purpose of being ultra budget. I bought the CPU years ago new for $130 which is insane bang for buck, but they do perform funky in some games. If you're having issues you feel are CPU related feel free to post your CPU model below in the comments and your experiences.