Earlier quoted context omitted.
Windows Explorer has been so slow that I actively avoid using it and use the command prompt instead. Even on an SSD, opening a folder sometimes takes several seconds while Explorer scans that folder with a progress bar on the address bar (and does I-don’t-know-what in the background). I see this happening for downloads and many other folders. I use Keypirinha , Everything , and other tools to get work done.
In many of those cases it's shell extensions installed by other apps that make Explorer slow. I forgot how you can check that, but you can.
Which is fine, but it gets slow as hell. I have a brand new very fast machine and all the sudden explorer was getting so terrible. I downloaded something to disable the dropbox shell extensions and back to very nice performance.