i have an i7 CPU and have been frustrated with use of the develop module - when i click and hold on a slider, such as exposure, it takes 1-1.5 seconds for each update to be shown on the display.:mad2: It makes it very difficult to make adjustments due to having to move the slider, wait for results, overshoot, go back etc. I noticed when I am moving the slider, only ONE of my eight cores is being used. it is at 100% where the rest are at under 2-3%. i am running win 8 RC 64bit , but if memory serves, this was happening on this machine when i was running Win 7 64-bit machine. Can someone confirm this is the current behavior, and if so , why can't these processes be multi-threaded? We are talking about significant performance boost here.. '' All latest updates for windows and Video card (tried beta drivers also) I have a 7770 video card 1GB video card, 16GB Ram, photos and catalog are on separate solid state drives. I was excited that 4.1 was listed to address performance issues with development tab. Strange thing is prior to version 4 the performance was not nearly as bad. Photos were converted to v4 lightroom from v3 (no ! is shown.) Any ideas? I paid for the upgrade, and features are better, but performance is unacceptable. I have ninja IT skills (IT Architect) so let me know if there is anything I can provide to help diagnose.