Switch to the "x86-64 - Chromium + 64-bit binaries" beta branch.

How to do it:
Steam Library → Right-click Garry's Mod → Properties → Betas → Select "x86-64 - Chromium + 64-bit binaries"

Steam will automatically begin updating Garry's Mod to the 64-bit version.

Click here[github.com] to open the official GitHub releases page.

Steam will prompt you with a warning — click "Continue to external site".

Once you're on the GitHub page, download the latest version of the mod.
Look for the file named "vphysics_jolt_0.20_gmod_win64.zip" (or the latest version with a similar name).

Click the filename to begin the download. Save the archive anywhere you like — you won’t need it after installation.


Open the downloaded ZIP archive.

Inside the archive, navigate to: bin/win64

Now open your Garry's Mod directory and go to the same folder:
...\GarrysMod\bin\win64

If the folder exists, drag and drop the files from the archive into it, replacing any existing files.

Done! The mod is now installed.

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⚠ Important Note:
If the win64 folder is missing from your Garry's Mod directory, it means you're still using the 32-bit version of the game.
Do not create the folder manually — instead, make sure you've selected the correct beta branch as described in Step 1.

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Switch back to the default (non-beta) version:

How to:
Steam Library → Right-click Garry's Mod → Properties → Betas → Select "None"