Is your internet connection on another device really slow when netflix is playing?

[Tom]

When watching things on Netflix your streaming media, essentially, your downloading the movie while watching it.

Now when your downloading, this takes up your networks resources, so when your actively downloading something this will always affect your speedtest results in a negative way. The only way to get accurate speed tests results is to do it while not down/uploading anything. If you do, the speedtest will show alot slower than what it should be.