I have a Zotac ZBOX ID84 with Intel D2550 proc and Nvidia GT520M GPU, 2GB memory and 320GB hard disk.

I tried XBMCbuntu first and it ran perfectly for a few months until I started to mess around with the Terminal. After a re-install I could get the HDMI sound to work again so I installed the latest version of Ubuntu (13.04) instead.

That worked fine. The sound and everything worked right away, but the interface of Ubuntu is sluggish and XBMC doesn't run as good as it did in XBMCbuntu. The video playback is slow and it stutters. It speeds up and slows down with the complexity of the video.

So, the PC is more than capable to run XBMC and play the videos, but something in Ubuntu (GUI?) slows it down to an unusable pace.

Can anybody tell me what I can do to speed things up? Since I'm new to Ubuntu I have no clue where to start looking.