Since I've upgraded to LR5, the cloning tool and adjustment brush have become almost useless. They behave as if in slow motion, taking sometimes 3-5 seconds or more to react to a movement or click. Sometimes, after I've started it'll catch up, but when processing a few hundred images, those 3-5 seconds sure add up. I'm not used to waiting. Everything else seem to be working fine.
I'm on a MacPro, dual 2.8GHz Quad-Core Xeon processors, 20GB of RAM. My LR catalog is on a drive that is only half full, however my images are on a drive that is almost completely full. Could that have anything to do with it? If not, any other suggestions?