I recently bought archer C6 1200 to improve my home connectivity. However, the max connection speed of 72Mbos on 2.4Ghz and 433Mbps on 5Ghz is way below the committed levels of 300Mbps and 867Mbps. Consequently, my actual transfer rate on 2.4Ghz is between 15-30Mbps at a distance of 20ft (straight without any hinderance) and max 30-40Mbps as I walk within 5ft distance; thisnis even lower than my previous super basic single band router. 5Ghz is giving me 70-85Mbps on 100Mbps connection, but it disconnects frequentlyas I walk about 20ft from router (again no hinderance). 

Have gone through some of the precious posts, but didn't get any answer. These connection speeds (bandwidth) are the lowest for Wireless-N (2.4Ghz) and Wireless-AC (5Ghz). Any specific reason Imy connection bandwidth is on the lowest side for each? With 72Mbps capping, I can surely not get the max speed that my ISP provides. Let me know if it can't move up, I will consider replacing or returning it. FYI - I have tried changing channels (1,6,11) and frequencies for 2.4 GHz but to no benefit.