After several months of acceptable behavior with V5.0.2, the performance (especially skips and menu jumps) became *terrible*. I was stumped. I posted the problem, received a lot of helpful ideas, but no improvement.
In frustration, I ran Executive Software Diskeeper and clicked on menu entries. Diskeeper runs every night at 2am, so the disks are not fragmented. Then I clicked on MFT/Boot File. Viola! My MFT (master file table) was 99% filled. Never thought about the 5,000 photos (plus thumbnails, of course) that I uploaded over the past several weeks. That blew up the MFT and Windows didn't expand it.
Well, 10 minutes later, Diskeeper had expanded by 20x. Problem solved!

Performance is good again.
Hope this helps someone else.
--John