Lightroom 6 seems to be in comparison to Lightroom 5 to be much slower.
Loading the catalog needs much more time. Displaying images in full resolution
needs more time. Sometimes image modifications gets displayed jerk (and I have
a very good grafics card!). Images gets sometimes not displayed (for example
if an image from the face recognizion gets selected to see the whole image),...
Would it be possible to add a switch to alternatively use the old Lightroom 5
routines? Would be a fine option to get the program to work with the old
Is your Lightroom updated to the latest version 6.0.1? Check under Help menu > About.
See if the suggestions here help, regarding your graphics card and driver:
Also, are you connected to the Internet? Sometimes LR6 has been sluggish if not (needs to be fixed by Adobe).
Hope that helps!