My previous version was 0.14 or so. I installed 0.17.1 and it seemed to delete all of the blocks on the SDD and then download them from scratch. I have an i3 Intel Processor, 4 GB RAM, 320 SSD HD, so fairly new computer about 1-2 years old. I have set the memory in Bitcoin Core to 2000MB in the settings.
In my task manager the Disk IO is maxed out at 100%. I have 8 connections to the network. Time to sync says 4 weeks. Not sure why it is taking so long. Been 1.5 days.