Anyone on VIVID 350 can you advise on what download speeds you are getting please (just a big file like itunes). I seem to max out at about 10-12 mb/s which by my reckoning does not correspond to the 380 mbits/s on the speedtest. On Sky at 80/20 I get 8 mb/s downloads...so I should be getting about 35 mb/s downloads on 350/20.
Are you speed testing multiple or single connection download speeds? If using say speedtest.net then that uses many so test using thinkbroadband.com (shows 1 and 6), speedof.me (uses 1) or dslreports.com (last one must be set to use 1 not the default 6 connections for download testing in its options).
It's not uncommon for VM connections to be much slower on a single connection than using multiple and this affects downloads where only a single connection can/is used (a lot of video streaming, most downloads with out a special download tool etc).