Why do my downloads on steam “build up” to my Internets actual speed? Why doesn’t it just instantly jump to 10Mb/s?
In: Technology
> Why doesn’t it just instantly jump to 10Mb/s?
But is that really your max download speed?
[*vsauce jingle*](https://www.youtube.com/watch?v=32EJg8lqJgQ)
The traffic isn’t just between your PC and the ISP’s own router. The download process needs to account for the limitations of every single network device and cable/wireless link your traffic goes through. The max speed can even change mid-download if a line goes down and the routing changes!
In order to avoid overwhelming the channel and causing a major lock-up, the TCP protocol includes [slow starting](https://en.wikipedia.org/wiki/TCP_congestion_control#Slow_start) that first tries sending stuff slower and sees if everything gets through, then ramps up until some packets don’t arrive on time. After that it dials back a bit to a previously known good transmission rate.
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