I'm running an Ubuntu 14.04 LTS (32 bit) VirtualBox guest with >10GB storage and 2GB RAM on a Win7 (64-bit) laptop supporting VT-X. Like many others upgrading to 14.04 LTS noted here, Ubuntu runs very slow. The pace was tolerable until now.

I've enabled 3D Acceleration and set the controller SATA setting to use Host I/O Cache. I've toggled 32 and 64 bit. I don't know what else could be causing the performance decline as I have other guest operating systems working fine on same box.

Any suggestions are welcomed.

  • It might be because of relatively low system (host) memory causing page file activity - keep in mind that probably a part of your systems' RAM is shared with GPU. Check windows page file usage, Also, antivirus and (windows)firewall programs can cause fluctuations in performance. Try turning off firewall (BAD IDEA security wise- only do this to test) or install "lighter" alternatives.
    – hmayag
    Aug 27, 2015 at 21:25
  • @hmayag I think the pagefile was the problem. My Ubuntu VDI is 13GB. Is there a recommended maximum pagefile size setting for Ubuntu guests running on Win7 hosts?
    – Catalyx
    Aug 28, 2015 at 1:04
  • General rule: Give any OS about twice the size of RAM in pagefile. In other words, for 2GB of RAM, give a 4GB swap file in Ubuntu. In Windows, if you have 8GB of RAM, get 16GB of pagefile.
    – Daniel
    Aug 28, 2015 at 16:12
  • Yours is an issue of limited RAM. The size of the VDI file is not relevant. It may sound counter intuitive, but decreasing the amount of RAM you allocate to the VM from 2GB to 1.5GB may actually result in better performance because it will reduce the need for the HOST system to swap out memory to the pagefile. Also it will help if you minimize the number of programs that run parallel with the VM (ie shut down all other programs when running virualbox).
    – hmayag
    Aug 28, 2015 at 21:06

1 Answer 1


I've had the same issue. Install the VirtualBox guest additions and reboot. That solved the problem for me with Ubuntu 15.04, and it should work just fine for 14.04.

Also, 14.04 had some issues with GPU usage. If the above doesn't work, try upgrading to 14.10 or 15.04, they seemed to fix that problem.

  • Reinstalling and updating VBox Guest Additions improved performance a good bit, though it led to other host memory issues that were ultimately fixed. I think what @hmayag commented above is a factor as the host's limited shared GPU seems to be taxed heavily by 14.04 LTS's UI animations and relates to the noted memory problem.
    – Catalyx
    Aug 28, 2015 at 0:58
  • After upgrading to 14.10, the speed significantly improved. It seems 14.04 LTS does not work well with VBox 4.3.30 on hosts with limited shared GPUs.
    – Catalyx
    Aug 30, 2015 at 20:05

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