Ed Venglik has built the mancave of his dreams — five big-screen smart TVs, Apple TV streaming boxes, DVD players, Sonos music system, an Xbox, a Wii and remote-controlled lighting. To run it all, Venglik is dumping his already beefy download speed of 150 megabits per second for download power on steroids. He’s switching to Comcast’s Gigabit Pro — a 2-gigabit speed demon so fast a two-hour high definition movie can be downloaded in 12 seconds or a 30-minute “Parks and Recreation” episode in just two. “It’s a little over the top,” the married Johns Creek father of three admits. “But I’m just keeping up with the demands of things we want to do quickly.”