Very slow upload speeds when connected to my work computer through ethernet cable.

So..I am pretty good at trouble shooting issues but this is causing me to not have the speeds I need to work.  I have 150 download speeds and 10 upload speeds (what I pay for)...when I connect to any computer with ethernet or wifi, I'm getting great speeds (although tons of variations from 3-9.9 upload).  When I connect to my work computer, the upload speeds run from 2.5-7.3, with great download speeds, but uploads change so much in the same minute (I run the speed test 3-5 times right after each other and I get from 2.5, 5, 2.5, 2.5, 7 2.5) so it is not consistent.,..work requires at least 3, but it changes so much it knocks me off the network and I loose calls constantly. I have bought new cords, changed ports, checked all of the lines in and outside of the house.  I was also looking up info and it said that port 443 is closed on accounts according to cox, but since my personal computer does not have issues, why would my work computer? I feel like there is something on the computer, but also the inconsistent speeds are not helping. Please help so I can work again! :)))