why dont you play with the settings, the most reliable ive found even on my 120mb down and 10mb up is 1mb to mobile phone, i would limit the settings to from 720kbs to 1.5mb up and try that.
If your brave and its a member of the family, you could also give them the sign in details to your server and allow them to pin the folders over (or you could send them directly over from your server if your a premium member), i do this with the inlaws as there connection is very iffy.
Ive got mine running (for well over a year now) on a mac mini 2012 ivy bridge, it converts hd inc 1080p very quickly. That is married up to a 12tb nas array.