Upload Zip to Dropbox using Powershell

As for the connection speed for the upload requests, note that your connection speed to Dropbox depends on the routing you get between your ISP and our servers, and may be slower than your ISP's rated speeds. Sometimes resetting or retrying your connection gets you a different route and better speeds, but that is outside of our control. Some ISPs also throttle sustained connections so if you see an initial high connection speed followed by lower speeds, that could be the reason.

Also, I see you may be uploading multiple files to Dropbox serially in that 'foreach' loop. Check out the Performance Guide for ways you may be able to optimize this, e.g., by uploading files in parallel and then committing them all at once.

Otherwise, I see there is more code here than for just the Dropbox upload itself, but we can't offer help with that part unfortunately, as that's not about the Dropbox API.