RB 532 not putting out more that 14 mbs

I have a signal coming in from a 100 mpbs cable modem from my service provider coming into my property. When I hook up directly to the modem and do a speed test, I can get 80-85 mbps. When I put the RB 532 into the mix, coming straight out of the router board I can only get 14 mbps…Any thoughts as to why?