download speed "freeze-ups"

I believe you are mixing things up.  I am on a medium plan, 500 MBPS down, and 50 MBPS up. I am able to stream without issue, as you should be able to do at 100 mbps download. 

https://www.speedtest.net/result/16662595775 

That being said, they cannot "CRAM" data. When you are receiving information from a site on the internet, It comes from that site, through a myriad of routers till it reaches cox, and gets directed to you. Your internet is usually on an HFC, (hybrid Fiber Coax), and in most areas runs on dark fiber up to a point, where it's broken down to coax and fed to the homes. This can handle MANY GIGABYTES of data, so trust me when I tell you, 100 mbps is a drop in the bucket. 

So, if you would like some help in ascertaining if it's a cox issue, an equipment issue, or a possible issue with WiFi being stepped on by something causing your issues, I will be glad to help. What I mean being stepped on, 2.4 as well as 5 ghz, is used by cordless phones, microwave ovens, bluetooth devices, cordless kb's and mice, game controllers baby monitors garage door openers, rc toys, and every neighbor with WiFi as well. That's a LOT of noise on the WiFi channels, but there are many things that can be done to help ensure that devices in your home are getting a good enough signal to work ok. 

That being said, what modem/router are you using? Is your WiFi router out in the open, not behind anything or in a cabinet or under anything? It has to be out in the open, and set as high as you can place it. Anything in between the WiFi router and the device talking to it, will block the signal. If you have a smart box, (not really smart), ensure your WiFi router is OUTSIDE of that box. (Think Faraday cage). Sometimes simply ensuring the best placement of the router, can fix many wifi speed issues that cause devices to hiccup while streaming media.