I'm moving into a new house with my Girlfriend next month, and I finally have the chance to have a decent internet connection! When I'm at her current house, if she's playing Leauge of Legends and I try doing anything moderately bandwidth-intensive (playing TF2 is fine, but Google Drive syncs just kill her game and cause massive lag spikes) it's a no go.

Her broadband seems great the rest of the time so I'm guessing this is the router not splitting the bandwidth fairly and it's first come first served. I saw this when using a BT home hub in my old job, and someone on the community recommended a Draytek router which fixed the problem.