Messing around with the new release of LR4 today. I'm noticing a real slow down when using the exposure sliders, they become very sticky and sluggish, taking seconds to respond. It's almost unusable. I'm on an HP Z800, 6 core Xeon, Nvidia FX3800, Win 7 Pro 64. If I switch off my secondary monitor these problems go away, it's fine.
I've noticed that this issue has been mentioned on the Adobe forum.
I'm working on an older image, Hasselblad CFV that has been switched to 2012 process, and it would seem that adding noise reduction and sharpening makes the exposure sliders particularly sluggish, so my workaround will be to hold off on certain processes until as late as possible and failing that switch to a single monitor setup for now, but this must be a bug, I never had these problems with LR3.
Anyone having similar trouble? Is this happening with Macs?