I am a longtime LR user and have been using a fast Win10 PC (32GB DDR4 RAM, SSD drives, GT 740 video, i7 processor etc) and the latest LR update (or is it the one just before it) drastically changed the speed that I can go from image to image in the Develop module.
I've read about a memory leak problem but with 32GB of 2133 speed DDR4 memory I never notice much RAM usage (maybe 25%?) so I do not think that this is the issue. Something changed in LR and Adobe needs to fix it. The slowdown really affects my work and I earn my living this way! Adobe, please help us!
Try unchecking the option Preferences > Performance > Use Graphics Processor.