Julie, those are good suggestions but for some of us, or at least myself; the problem was sudden with the update from LR 5.4 to 5.5, and then worse from 5.5 to 5.6. This means that our workflows were just fine before the update and something in the program is now not functioning as well. I know I was not experiencing such slowdowns before the update, because I deeply regret updating. I thought it may have been a plugin I downloaded but I've since disabled all plugins but one that I've always used. I did recently install Paddy, but again I've disabled the plugin.
I don't do any serious stuff, some images do have LOTS of spot healing, but in my current culling job none are that extensive. I understand and recognize when those types of images cause slowdowns. What I've been doing lately is going through a few thousand images, and when I updated to 5.5, and then 5.6, Lightroom stopped occasionally crashing and started behaving like molasses. More details below:
5.4 would crash when I would occasionally hit CTRL+Z after dragging the view in the navigator without letting go. I'd be holding the navigator, peering around the image with my tablet, then I'd hit CTRL+Z and it would crash. Sometimes it would crash for no reason what so ever. I thought perhaps I corrupted the program because I had some RAM issues. I've sorted that mostly and I'm running on a seemingly good 8GB.
Now when I updated to 5.5, no more random crashes, but it began to lag. When I'd be going from Grid to Loupe view or switching from Loupe to Survey on my second monitor, it progressively got worse. I didn't notice it so much until I updated to 5.6, thinking "oh good another update should help."
Once I updated again, after about 30 minutes to an hour of working, Lightroom will take about ten seconds or longer to respond to CTRL+F, for fullscreen. it will often take me a whole minute or MORE to go from fullscreen to windowed mode, or vice-versa. It's so bad sometimes the program will gray-out (not responding) and I will have to get up from my desk for five minutes while my i7 3770k CPU tries to sort through the mess Lightroom is making, I assume. When I get back things are sitting there as they should be, but still slow to respond. I also notice possible slowdowns after using another program, like Internet Explorer. I will try a session without using any other programs but I believe it happens regardless.
After a slowdown, I close Lightroom, let it back my catalog up encase it's screwed up, then I restart the program. Once restarted I get another 30-60 minutes before it needs help again. Anywhere from 60-150 photos of mostly culling and cropping, but honestly just basic tone adjustments to groups of images (20-100) and some crops. No severe touchups. It's a SEVERE slowdown especially for the job I'm on (few thousand images) and I'm nervous to attempt a downgrade because I've never done that before and I have a client waiting on these images, so any troubleshooting will sadly have to wait.
Finally, I do see slowdowns after switching from the crop tool back to loupe, I think it feels like slowdowns correlate to me switching modules and switching views. It works decent, albeit a bit laggy, and after about 45 minutes on average it goes horribly wrong and I have to promptly restart Lightroom.
I hope this helps I'm very tired, it's been a very long day.
