Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I own a Thinkpad T420s with 8GB RAM, 160 GB SSD and a quite fast i7 processor. Summa summarum a very fast computer that works perfectly. Now, I am not very impressed by the performance of my Ubuntu 12.04 virtual machine running on VirtualBox 4.1.18. I assume that Virtual Machines are always a bit slower than the guest system, still I think it should be more performant given the hardware settings I give it:

  • 4096 MB RAM

  • 1 CPU without CPU limitation (I would like to give it more but then it does not seem to work - I am not experienced in this maybe somebody could give me advice on this too)

  • Activated PAE/NX, VT-x/AMD-V and Nested Paging

  • 96 MB Graphics Memory (no 2D or 3D acceleration)

  • ~ 14 GB disk space, currently about 7 GB are used

  • EDIT: Guest additions installed

Maybe I misconfigured something, could you give me a hint please? Thanks!

Edit: What I mean by slow is that for example switching tabs in the browser (whether FF or Chrome) only goes with a 0.5s delay or something, as well as switching application windows and/or double-clicking applications in the dock to get all open windows.. opening Aptana takes about a minute whereas opening something like Photoshop on the guest system takes 5 seconds

share|improve this question

Based on what I saw for I/O, VirtualBox vs VMWare, VMWare wins hands down for basic operation (looks like its losing out on heavy graphics computation - but could be due to configuration).

I'd suggest first trying out the free VMWare Player instead of VirtualBox and see how your performance is. For Ubuntu, you're not going to need that much resource. I usually pair 1 CPU to 1GB RAM.

I'd start with 1 CPU core + 1GB RAM for your Ubuntu, enable GPU acceleration, shouldn't be any problems running X.

For your VM guest OS, I suggest trying Lubuntu to for a lightweight Linux, X ready loaded, and ephiphany browser (Chrome/Firefox too) runs nicely. You could load it up with server right off the bat too and it will hum, main hit to performance would be heavy graphics, but it should be able to handle compute and I/O well for its size. You should get reasonable performance out of this VMWare VM.

Keep in mind with virtualization, your main performance hit will be running your VMs on top of Windows 7.

There are other solutions if you aren't tied to your Windows 7. The "bare metal" solutions will provide you with the best performance on VMs as the OS hosting the VMs is extremely thin.

Some versions of this:

  • VMWare vSphere Hypervisor (basic free, full bare metal)
  • Citrix XenServer (basic free, full bare metal)
  • Linux + Xen or KVM (open source, I'd suggest Lubuntu, Xen, virt-manager)
  • Microsoft Hyper-V 2008 (sitting on a Windows Server 2008, basic free)

With the exception of a custom Lubuntu/xen/virt-manager setup, (and I haven't research Microsoft Hyper-V 2008 yet), you won't have access to a VM view on the host OS. Which is a total bummer if you want to virtualize all your OSes, but I think paid versions may provide this feature.

(sorry, had to remove a bunch of hyperlinks due to my low reputation)

share|improve this answer
Hey, thanks for your exhaustive answer. The thing is, I do not really want to reinstall Ubuntu or another guest system, and do not want to switch my host system either. If I had spare time or would be setting up a completely new work place, that would be an option. Might come in handy for other users though, thanks! – wnstnsmth Oct 2 '12 at 5:34
I'd still suggest trying VMWare instead, I run Ubuntu VMs on my Win7 in VMWare Player without issue. Single CPU, 1GB, and it runs Lubuntu fine. I'm sure if you put 4CPU + 4GB it would run fine (though your host machine may slow down). I'd also suggest isolating the CPUs you are using. Set the CPU affinity on your VMs to say CPU5-8, and set the affinity on your heavy apps to CPU 1-4. Run some perfmon on your CPUs to see what happens when under heavier load. – sonjz Oct 3 '12 at 0:44

An important thing to do is "Install Guest Additions". With Guest Additions, your mouse functionality improves massively making it lag less. And, try what Aaron has to say.

share|improve this answer
I already had them installed for quite a long time, sorry not to have mentioned that. Without them, I could not really use it because the resolution would be too low, right? – wnstnsmth Oct 2 '12 at 5:34
Yes and like I said it improves mouse functionality.Just an FYI, this page tells you why Guest additions is epic. As for your configurations, I cant see what's wrong. – Gutsygibbon Oct 2 '12 at 15:46
Yes and like I said I already had them installed :p – wnstnsmth Oct 3 '12 at 5:30
Well then try messing around with some that normally helps with VMs. – Gutsygibbon Oct 3 '12 at 19:58

I'd suggest giving it some more graphics memory -- at least 128MB, though 256 or more would be better -- and enabling whatever graphics acceleration options are available. In particular, leaving 2D acceleration turned off is going to hurt.

share|improve this answer
I can only set the graphics memory to 128 MB - that might be the issue. My T420s comes with a NVS 4200M GPU with 1GB of dedicated DDR3 and a "CPU-integrated HD Graphics 3000, which can dynamically command between 64MB and 1,696MB of system memory for its purposes", using Optimus technology to dynamically switch between what is needed. Maybe I could somehow tell Virtual Box to use the nVidia card, but that might be a whole other question. Concerning 2D acceleration, that does not work since it says it's only for Windows guests and will be deactivated. – wnstnsmth Oct 2 '12 at 5:42

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.