I've just upgraded from LR3 to LR4.1, and can't believe how slow this software works! It can take 20 seconds to do a simple crop. I have processor widget displays and after a slider has been moved the needle goes well into the red usually 100% usage for 10, 15, sometimes 30 seconds before gradually recovering to the minimum. It's impossible to finely adjust a slider as you can't see the effect for all of these seconds so you give up and move on to the next slider. This deprecates the resultant image so much compared with what you should be able to achieve.LR3 worked very well and quickly. I have done all suggested things to improve the processing health of my computers to no avail.If Adobe does not release a solution very soon I will be moving to Apple software as I cannot afford the 10 fold increase in image editing time.How Can Adobe release software with such abysmal performance!?