Several insiders have reached out to us to note that Cablevision will be offering a significant new Optimum Online speed tier starting on Monday. Dubbed "Boost Plus," the service will offer subscribers downstream speeds of 50 Mbps and upstream speeds of 8 Mbps. That puts the new tier in between Optimum Online's Boost tier at 30 Mbps downstream, and 5 Mbps upstream -- and the company's Ultra tier, which offers 101 Mbps downstream and 15 Mbps upstream. Our sources had no information on price, and it's unclear whether the tier will have the steep $300 installation fee associated with their Ultra tier. Carriers are still trying to find the sweet spot for bleeding edge broadband users, with 100 Mbps tiers (in part due to price) seeing relatively little uptake so far. Cablevision wouldn't comment on the information, though you shouldn't have long to wait for confirmation.