I see your charts, chief. But where are those numbers even coming into play? Just by copying files onto the drive or off of it? Accessing files?
Depends what you're copying the files to or from, but yes, it can be a factor there. The things that most people would notice is in application launching, or multitasking while running another task that hits the disk a lot (for example if you started launching apps WHILE copying files, or tried to launch several apps at once).
Differences in random io performance can also make a noticeable difference in boot/login speed.
The differences in faster and slower disks are less noticeable for single-user desktops with modern OSes as most are much better at caching, prefetching, and generally making use of available memory than, say, 10 years ago. Most of what I posted would be MUCH more noticeable on a heavily utilized server.
