While Dropbox is uploading, it takes the whole bandwidth (1000kB/s) even if the limit is set to 'automatic' or any numeric value. At this very moment it is set to 300 and I read 996 by a bw meter. This blocks every internet activity on my pc (and on every other home device connected, as well).
I'm using Dropbox v132.4.3800 and the status (while uploading) is "sync in progress", the small blue circlet on the sys icon.
Here you can see the bw set to 300 and the actual upload speed measure (the green band is the history graph). In my opinion, there should be some kind of bug preventing dropbox from sensing or acting on the bw.
Options settings, where you can choose Kilobytes per second (kB/sec) or Kilobits per second (kbps):
The same speed of the former screeshot, but measured in kbps:
The ratio is 1/7.5, quite near the theoretical 1/8.
I tested the dropbox upload bw to a bunch of values around 132 KB/s and nothing changed, viceversa 10 or 20 had a heavy effect.
I feel that this could be the right way to run... I want to test it systematically, 10, 20, 30 and so on and then I'll report here. I also want to perform an internet speed test clean, with and without phones and tv connected.