First off, you need to find out if you can actually run 64-bit applications as well as check how much RAM you have. While most PCs produced in the last ten years can run 64-bit, you might have installed a 32-bit operating system, which will prevent you from running 64-bit applications without reinstalling the operating system.

Open the start menu, right click “Computer” and press “Properties”. Here, you will find some information about your PC, including RAM and if your operating system installation is 32-bit or 64-bit. Take note of your RAM, as we’ll need to know how much you have later on.



If you are running a 32-bit system, you will not be able to run Spiral Knights on 64-bit Java and this guide is not for you.

IMPORTANT! You will need to download from here! NOT from Java.com, RAR password: spiral
Windows[drive.google.com]
Linux[drive.google.com]
MacOS[drive.google.com]

Once it’s downloaded, you need to open your Spiral Knights installation folder. If you’re playing through Steam, this should be C:\Program Files (x86)\Steam\steamapps\common\Spiral Knights. If you’re playing the standalone version of the game, it should be C:\Program Files\Spiral Knights. You can open the folder through Steam by right clicking Spiral Knights in your library, opening Properties, going to the Local Files tab and clicking Browse local files…



In that directory, you’ll find a folder called java_vm. Rename it to java_vm_backup, in case we screw something up.



For Windows users: Go to Downloads folder and extract files from .rar archive we just downloaded (Java 8u251.rar). Now copy java_vm and extra.txt



Go back to SK installation directory and paste it in there. If you did everything correctly, Spiral Knights should be running on 64-bit Java!



If the game no longer boots, you probably didn’t follow the instructions properly, and you'll have to rename java_vm_backup folder back to java_vm in order to undo the recent changes.

Checking if the 64-bit Java installation is quite easy. Just start Spiral Knights and open the Task Manager by pressing Ctrl+Shift+Esc. Open the processes tab and sort by memory usage. You should find a java.exe process that’s using a decent amount of RAM. If it says java.exe *32, Spiral Knights is still running on 32-bit. If it just says java.exe, you’ve succeeded!

Next step is to make Spiral Knights make more use of your system. Go to your Spiral Knights installation folder and create a text file called extra.txt. Note that you’ll only have to name it extra if your system has extensions hidden. You can quickly see this by looking at digest.txt right above it. If it says digest.txt, create extra.txt. If it’s just digest, create just extra.

Open up the extra.txt and paste this:


Depending on how much free RAM your system has
You can replace Xms and Xmx values
Here are some examples below:

16 GB RAM

8 GB RAM

4 GB RAM

2 GB RAM

An example of my extra.txt file:


If you have less than 2GB RAM: Both Xms and Xmx should be 512M

The last two lines tells Spiral Knights to use several CPU cores for garbage collection.

Thanks for reading! If you’d like to know more, you can take a look at this old thread.[forums.spiralknights.com]

Also bear in mind that if you’re playing on Steam and use its Verify integrity of game cache function, it will restore back to 32-bit Java, in which case you’ll need to do this over again.

If you can't make this work, download KnightLauncher[github.com] and extract .jar file into your game directory. You might want to configure some settings from KnightLauncher though!
Like setting your desired memory, by default it'll be set to 512MB