I have already booted up an OS but find it too slow to work on. Is there a way to increase the RAM which was allocated to it initially?


Pretty easy to do.

  1. Power down the VM (the guest has to be off, not just not running but with a saved state).
  2. Discard 'Saved State'
  3. Open the VM's settings.
  4. Open the System tab.
  5. Change the "Base memory" value to however much RAM you want.

Remember, the VM will reserve all the RAM you allocate to it on your host, so make sure you have enough spare RAM. Most modern OSes will deal with the amount of RAM changing just fine, but you may still run in to trouble, so make a snapshot first.

  • 3
    Many settings are greyed out and cannot be altered. One must first do "Discard Saved State". This is safe because I shut the VM down previously. After that the RAM can be expanded. – mark4asp Jul 10 '17 at 18:49
  • With VirtualBox 5.2.4 I didn't need to discard the saved state. I just followed the list, except for point 2, and it worked. So maybe they changed it in recent versions. – Fabio says Reinstate Monica Aug 21 '18 at 18:47

In addition to Dennis M, to change Vm machine memory settings via command line, I used :

vboxmanage modifyvm "Centos7_Vanila" --memory 1000
  • Where "Centos7_Vanila" is my VM name.
  • To Get your imported / listed VMs run following command :

    vboxmanage list vms
  • Just a note: the default unit seems to be megabytes and it will fail if you try to add the unit like --memory 1000M. – Luc Mar 26 at 16:41

There is a fast way in terminal, I named the virtual machine "Android 8.1 Oreo", so just modify that on the following command:

vboxmanage modifyvm "Android 8.1 Oreo" --vram 256

I had a maximum of 128.

  • The question is not about VRAM. – gronostaj Dec 23 '19 at 13:46

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