Up to 200 Mbps download speed....I'm getting 40-45 Mbps MAX even in off peak times now...what gives?

We had a tech visit here a month or two ago due to our legacy box not having access to On Demand due to constant errors (CL-17, etc). He coupled together a newer coax line another tech ran in from the road and snaked that up through the floor to our only TV with a cable box on it (at the time a legacy one, now an X1 box). 

For a while things seemed to stay the same, but within the last week or so I decided to check my connection across multiple devices. On my hardwired PC I get around 27 Mbps download speed, my PS3 (also hardwired) gets 40 Mbps and my PS4 I have upstairs (hardwired via a 100 foot Cat 6 cable) gets 45 Mbps on a good day. Even our phone we have through Comcast gets around 35-40 Mbps and that's on our Wifi. 

So what could be the problem? I definitely would rather run a coax line upstairs and move my gateway (SBG6580, yes I know it's "old") upstairs while running a line downstairs and routing it to my other devices there. But at the same time I don't want to make anymore holes or run anymore cables. I've tried restarting the gateway, power cycling (unplugging, plugging it back in) it and nothing seems to get me back anywhere near what I was getting before (150+Mbps).

Any ideas would be appreciated. 

FYI: This gateway is wired to another new(er) line that another tech ran into the house from the road. There's actually quite a few lines cluttering up the corner of our basement where the cable lines come in from the road, including another as yet unfinished line that same tech that ran the one going to the gateway left dangling there.