As maximus says, post all your stats from your hub, let us know what devices you're using, etc. and we'll help you diagnose the issue.
It could be congestion in your area, but it's hard to say without this information.
Also, you would be wise to set up a TBB graph, it'll do a much better job of monitoring your connection than the ping test you've done:
http://www.thinkbroadband.com/ping