First test the speeds directly connected to the modem and not running through the router. 

Routers can cause slow downs, especially the R7900. 

Make sure on the R7900 that traffic monitoring, access control, parental controls and QoS are all disabled and then reboot the router. 

I would do what that other guy said by connecting your desktop, laptop or anything with a Ethernet port to your router and then test speed from that device and you should see the speed your paying for and also I have the T25 with a deco xe75 mesh router and sometimes during certain times in the day my Wi-Fi won't be at 800mbps but later on ill test speed again it will be at the speed that I pay for. That's why I prefer to connect my devices to the router with ethernet because you don't have to worry about the speeds constantly fluctuating. Also have you tried seeing if your router has a signal interference checker because that also might be a problem with your wifi speeds. 

I have tried that it is actually slower then wireless 

What actual speed do you get direct wired? 

if its lower, do you have a screen snip of the cable connections page and event logs?