UV editor performance problem


Im having serious performance problems with UV editor in blender. I have a game level that has around 5 000 faces. But when I try to make adjustments to the UV mesh, whole blender freezes for almost 20 seconds.
Is there any way that I can make the performance of UV editor better? like slicing UV mesh in several layers or so?

P.S. Separating objects is not an option for me because this will make rendering in game engine slower.

I had the same problem at the beginning and it was with a sphere lol. I uninstalled Blender in Windows and started running it on Ubuntu. It works like sugar.