AC3200 TriBand - LAN & WIFI Issue

Have been having issues with this router for some time now. My connection is supposed to be 400 mbps down and am only getting 70-90mbps via Direct and/or Wifi. Have replaced the Cat5e cabling, Contacted spectrum and it always points back to the router.  I have factory reset the device a few time now and still have the same results.   Firmware updated 1.0.4.18  also.  I would appreciate any help you guys can provide!!