VirtualBox - how to increase video memory?

Virtual Box supports up to 256 MB of video RAM. This can not be set using the slider of the Virtual Box Manager.

To make full use of all supported memory we can issue the following command in a terminal:

VBoxManage modifyvm "Name of VM" --vram 256

Before we change settings such as the video RAM a pre-existing virtual machine has to be shut down.

Note that for 3D video hardware acceleration from the guest addition's video driver the physical RAM of the host graphics card will be passed through. The video RAM settings of the virtual machine will not affect this.

You need to shut down the virtual OS before you can edit settings.

1. Stop the virtual machine and close virtualbox
2. Using a text editor like "Sublime Text" open YOUMACHINE.vbox. Make a backup beforehand.

3. Look for vram entry and change its value

   <Display VRAMSize="256" monitorCount="1" accelerate3D="true"
     accelerate2DVideo="false"/>
   

4. Save the file.

Now you can increase the video memory above 128.