You can change what the speedslider goes up to in the settings the default is 2 and you can change it up to x16. Disabling the Improve video interface feature disables the speedslider if you dont like it.
Edit: There was a bug before on Netflix where disabling the feature will put the speed to 1, I fixed that in the version 69. Hmm I tried to make the setting more intuitive by deviding by 10 but that made more errors, so i just wrote devide by ten above maybe I can look into it again.