I just installed Ubuntu 12.10 on my Virtualbox. Overall, Ubuntu 12.10 can run with all features enabled but I feel Ubuntu 12.10 runs very slowly when I tried to minimize or maximize the window. The visual effects seems not run smoothly on Virtualbox. I’ve tried to enable the 3D and increase the VRAM amount on the guest machine but still have this problem.
After searching on Google I found a simple way to disable the visual effects on Ubuntu 12.10. And by disabling this effects, now my Ubuntu 12.10 runs faster on Virtualbox. All you need is to install Compiz Config Setting Manager (CCSM). After CCSM is installed we can disable many effects that are active.
To install CCSM execute the following command on Terminal
sudo apt-get install compizconfig-settings-manager
Once finished, type ccsm to open the CCSM main window. Or you can also find the CCSM shortcut on the Dash menu.