[ubuntu] Running Ubuntu 12.10 as a virtual machine

I am currently using Kubuntu 12.10. I have installed Ubuntu 12.10 as a Virtual Machine. Ubuntu 12.10 installs fine, but performance is very sluggish.

I have gone in to compiz settings manager and turned off some of the effects.

I have installed Virtualbox Guest Additions

Any other ideas how I can improve performance?

I like using Kubuntu 12.10 as my main OS, but I would still like the ability to keep Ubuntu around.