Gigabit service cut in half

Ive been having this issue for over a month now. My gigabit service speed is being cut in half when connecting through a router. Hardwired to the modem is fine I get roughly 950/40.

 

Issue 1: Half gigabit Speed

 

- I've tried replacing my router with a negear xr700 previously a Linksys EA9500. I replaced all network cables with new Cat6 cables.  I've turned off all wireless radios and disconnected all hardwired devices leaving only one exclusive hardwired computer. I've also tried 2 different computers on that connection. 

 

- I've replaced my modem with a Motorola MB8600 Docsis 3.1  previously a Netgear CM1000 Docsis 3.1

 

- I've ran through mounds of tests with Netgear here: https://community.netgear.com/t5/Nighthawk-Pro-Gaming-Routers/Getting-half-my-service-speed-through-XR700-Xfinity-Gigabit/td-p/1908666.

 

Issue 2: High uploade ping spikes

 

- I'm also getting crazy ping spikes during loaded upload tests. Posted here but got no response: https://forums.xfinity.com/t5/Your-Home-Network/Trouble-with-connection-High-Latency/m-p/3328985

 

- Ping spikes started occuring a little over a month ago as well. Same results with Router/Modem/Cables being replaced. Same result connecting directly to the modem.

 

- Obviously not crucial but lag spikes make online games pretty bad which shows theres something going on. Again this was fine before it all started around a month ago.

 

I don't know where to go from here. Is there any sort reprovisioning required when connecting routers? I figure support stops at the modem but with this issue I see no point in paying for gigabit service. I'm in the Sacramento area.