That's a 16 channel modem. See under 'product description' for "16x4" channel bonding: http://www.amazon.com/Arris-DG1670A-Touchstone-Data-Gateway/dp/B00MI7JU72

While an 8 channel modem is theoretically capable of handling the speeds TWC is offering, the way they provision their network you must have a 16 channel modem to get 200x20 or 300x20; when their network recognizes an 8 channel modem is automatically puts it into a profile for 100x10 if you're authorized for a higher tier.