Aren’t they all sitting on the same server farm thing? One video will just creep along and click on another and it’s loaded in a few seconds. Or you’ll look at the bar and the streaming bar will be way ahead of the play bar but it still stops every few seconds.
Why?
Are the slow videos generally older ones, or with a small number of views?
Educated guess: frequently viewed videos are cached or held in fast storage. Older and more obscure videos are archived in slower storage, possibly a different data center than the one that is streaming it to you. So in some cases, it’s slower because the server is fetching it from elsewhere as it’s sending it to you.
I’ve experienced this now and again with YouTube. This particular problem can’t be server-related as the freezing occurs when most of the video is already cached and sometimes when it’s all cached. Sometimes you get a message, ‘An error has occurred’. Then you have to reload the video. Most times you don’t and you just have to stare at that annoying little spinner circling around while the video halts. It only happens rarely with me but it’s damned annoying.
This is entirely unconnected to slow streaming, which is something else entirely. I have noticed that the servers can have different speeds but I rarely have streaming problems with YT, although there is a particular time of day when all the streaming noticeably slows down a little, peak time I guess.
Your guess is accurate. YouTube uses CDN’s for the more popular videos. That means that the quickly loading videos might be transmitted to you from just about anywhere, maybe even some random data center just down the street from you. The slower to load videos that occasionally pause might be coming from much further away, from a much slower storage source, through a much slower connection.
I have experienced that on my laptop which I older…but my Kindle never stalls, never!! Is your computer older?
It might also be a quality thing. Youtube videos can be anywhere from 240p to 1080p.
Its intentional. can be worse depending on the quality of your connection but it’s intended to discourage the ‘downloafers’
I’m sorry if I’m misunderstanding this but…
Do you watch youtube videos on your kindle? 
Kindle FIRE is a regular tablet, sort of like an iPad but it runs Android.
If the video is already loaded ahead of the playout, you can’t blame a delay on the loading speed, to wit:
I was addressing the first part of his query, before the part you quoted.
As for what you quoted, it could be a number of things. One out-of-the-box thing to try is to ditch the regular Flash-based YouTube, and join the HTML5 YouTube Trial. Though if the problem is because his PC is old, slow, under-resourced, and/or outdated, this probably wouldn’t work at all.
(Too late for ETA): Another experimental thing to try might be this.
Quintas, when the playout halts, have you checked your CPU usage? Background tasks? If the data has been downloaded, but isn’t playing, maybe it’s in your system.
Yes I watch You Tube videos everyday on my Kindle Fire. Never stalls on me! But You Tube stalls all the time on my laptop.