Internet randomly stopping downloads?

[JacobGunther12]

I am downloading an update for CS:GO and and randomly my internet starts slowing down then about 5 seconds later it starts slowly going back up. Proof: http://i.imgur.com/WGmTZzv.png

[DaveLembke]

So much can cause this... looks to be throttling. Could be ISP or Steam, or others on network that your on using bandwidth at same time as download. For example netflix and other streaming content can request downloads of segments of the info to cache to play and at just about timed intervals it will request the next segment of the stream to cache to play as the prior segment has played out. This will cause up and down speeds.

[Geek-9pm]

This will cause up and down speeds.

Another set of ideas:
http://lifehacker.com/why-is-my-internet-suddenly-so-slow-1525144792
Brut there is no sure answer.

IMO you may have to change to another ISP.