Slow speeds on gigabit plan Xfi gateway

Hello!

xfi gateway mode: CGM4331COM

I've searched the forums and found some very similar posts, most of which are unanswered. So, I thought I would try my luck.

I just moved to a new house and upgraded to the gigabit plan. I set up the Xfi gateway and was immediately impressed with the wifi speeds (500 ish mbps), of course I haven't seen those speeds since the inital test. Now I get bet ween 200 and 300 on wifi and I'm very lucky if I get over 200 on LAN. I'm not worried about wifi speeds, because, well.... its wifi and I bought 1000 feet of cat 7 to run everywhere. 

I've tested this with three differen't Windows 10 PCs, all of which have up to date drivers and gigabit capable network cards. I have a catalyst 3560 switch with all three PCs wired directly to the switch. I ran various iperf tests and I'm getting gigabit speeds on all three PCs.

The iperf tests confirms that there are no issues with the PCs or the cables that I am using. 

I wanted to make sure the above statement gets read. I can move any of the PCs to connect directly to the Xfi gateway and my speed doesn't even come close to gigabit, I'm usually around the 100 - 200 mbps range on wired LAN. 

The 'speed test to home' says I'm getting ~110% of my plan speeds, around 1100 mbps download speed (I very much doubt this is accurate).  So either that test is completely false or there is something seriously wrong with the LAN ports on the Xfi gateway.

My question is this: Is it possible to order my own modem to replace this gateway? Or, if someone knows of some kind of magical hammer I could use to beat this thing into submission? 

My troubelshooting steps:

Power cycled PCs and Gateway multiple times.

Updated PC drivers

Unboxed multiple PCs and switch to run iperf tests

Put the gateway in bridge mode and enabled routing on my Cisco switch

Any assistance would be greately appreciated!