Having speed issues, I have 1gig speed from Spectrum, when plugged directly into the modem I get 875 to 950mbs. When the router is plugged into the modem and I do the built in speed test I get 542mbs. I loose over 300mbs. I used the cable that cam with the router and even changed it to a Cat5 with the same exact results. 
When I do a speed test via WiFi, I get anywhere from 200 to 500mbs. 
Any thoughts onwhy I am losing some much mbs from the modem to the router? 
Any fix suggestions? 
 

thanks