Ubuntu 14.04: very slow UI in Oracle VirtualBox

Enable 3D acceleration from virtual machine setting worked! I haven't tried that because in 12.04 I didn't have that selected so I thought it should work without it.

Also, I found the following helped for me. Enable the use of the Host IO cache for the SATA controller for the virtual disk.

Watch out for the "Execution Cap" setting under the processor setting for the virtual machine. I stumbled upon a user having it set to 1% when it normally should be at 100%.

You can find it under 'System'->'Processor'->'Execution Cap'. It's a slider.

Sorry for my ugly theme.