Secret performance tip: disable the GPU in Lightroom preferences.
Almost an identical system to mine, and I have the same problems.
Win 8.1 pro 64
i7-2600 3.4 GHz
Raid 1 3tb storgage
Nvidia GTX 560 Ti 1gb vram
Same performance with or without GPU enabled.
First, GPU is off.
i7 8core 1.74ghz
My system is much older but I also see lots and lots of lag time in doing anything. LR CC is just about unusable. I'm about to revert to using LR5 again, which is unfortunate, because I've done a few hours of work in a few catalogs.
It would be impossible to list what is slower beacuse EVERYTHING is slower and take 3x or 4x as long. Just scrolling the scrollbars on the left tool tray can make it freeze up for 5 seconds.
I never had this problem with LR4 and LR5.
My images are on an external drive (HDD, not SDD) and I used to be able to tell when reading/writing was an issue. Now, just about anything I do causes it to freeze to the point that Windows adds "Not Responding" to the title bar.
I should note that I also watch the CPU load while the program is frozen and its usually not doing anything. However, the disk usage is spiking like crazy and for no reason. It just doesn't make sense. It should not take 4 seconds to add a star to a photo and persist that to disk. Crazy.
The QA team really fell down on the job, or a product manager with some sway overrode some strenuous objections. This software should NOT have passed a performance test. No way, now how. (can you tell I'm software developer by trade?)
yay!! They updated LRCC/6 today. The slowness and latency appear to be gone!! Yay!!! I can get back to work!!
Has the update cleared the problem for you? im not seeing any perceptible change.
Yeah, completely fixed the random slowness for me. My machine is about half as powerful as yours. Win7 6GB Ram 8 core 1.7gz
To me it looked like the UI thread was being blocked anytime it did any background file reads or writes. Or something like that.
Will have to spend a bit more time with it to confirm one way or the other. Been turning GPU boost on and off as per previous recommendations and that seems to give me the best results. Not sure how that could be.
at some point I cleared the light room cache and that seemed to give me some boost as well.