From what I can find, the number of .pf files is 128, but I had 275 ... So, either MS changed the number or it wasn't cleaning up after itself.

Hey LMiller7,
I didn't think the two were related, until I manually cleaned up the \prefetch folder and it took superfetch 100% disk usage from a few mins to less than a min. Didn't seem like a...

After updating to FCU (1709) my startup time was slower and it appeared that Superfetch was the culprit. Superfetch was at 100% disk usage for a few mins, before it would finally calm down....