Can't get Ubuntu 13.04 to work in Virtual Box

I've installed Ubuntu 13.04 in Virtual Box (VB) and it is incredibly slow. I've Googled this and have found a ton of people that have this issue but no real solution. Some of the things I have tried to do include updating to the latest version of VB, installing guest additions, enabling 2D and/or 3D acceleration, increasing RAM/HD space to the VM, but the issue remains.

There are lots of suggestions, but I haven't come across a post that has a solution. It seems this issue has been outstanding since last year.

Would anyone know how to fix this issue?

Thank you