I am using a Samsung 300V with Core i7-2630QM CPU @ 2.00GHz x 8, Intel HD Graphics 3000, and 6 Gb of RAM. I use to have Ubuntu 11.10 installed and I did not have this problem. Recently when I changed to the latest Beta of Ubuntu 12.04 I noticed that sometimes when I move a window from one workspace to another, it vanishes for an instant and then appears, making it look like an interrupted movement (doesn't look fluid), which basically looks bad. It also happens if I change from workspace, without moving a window. Does anyone knows why this might be happening?