Lag? but from where?

[TheGoldenSheep3]

Yesterday I was playing Warframe and I started the "Octavia's Anthem" quest line and finished it today but when I started it the game started lagging horribly, so I thought "finishing it will stop the lag" it didn't, so I looked at my task manager and saw that Warframe is sending nothing to my router of course it is sending info, but only about every 20 seconds so I wondered if it was just Warframe or was it the router or even my computer I went on TF2 perfectly fine no lag sending data to the router, so it has to be Warframe, but what is causing it?