Granted my tablet is 2 or 3 years old now,
my sony smartphone only 5 months old.

I get onto U tube with my tablet using wi fi
and the video stops and starts... its useless to watch this way.

I turn off and then turn on my smartphone.
the same vid plays back without the slightest flaw or interuption.

A smaller pic of course but at least the vid keeps going from beginning to end.

My smartphone also has go google which allows me to use my voice to navigate the web.
cant seem to manage to get that on my tab
( though I think both devices are android.)

Big plus with the tab is the favourites button top right ... hit that and lots of bookmarks appear like football scores, U tube etc

cant yet figure out how to favourite or bookmark things on my smart phone

Maybe the bookmark icon is there but too small to see ?

Your post is open to wide interpretation but surely setting the Youtube quality lower(via the app maybe) will suit the tablet and broadband connection better so no stuttering occurs.

If you're asking why your tablet is so bad at playing youtube videos, it's probably a combination of poor processor speed, insufficient memory and poor data handling over wifi causing a bottleneck in the system somewhere.

I've noticed that Youtube is different on Tablets and smartphones too, although I don't use it enough to know much about it in detail.
Perhaps do a google search for "youtube android smartphone tutorial" to get more information about how to find all the features of youtube on a smartphone?

10 MINS on my tablet and Im usually angry and frustrated
with all the freeze ups..... the stop start of vid clips on U tube
etc .

At least the sony smartphone does seem to work better
but so small, Im prob never going to be able to bookmark fav
sites... Ill just have to keep barking out orders into go google to get where I want to go

Must be frustrating on buses and trains these days, I suspect
that lots of people are shouting out orders to " go google "

( asuming they have 3 g of course ) ( Im on wi fi)

Identical on my Nexus 7 tablet and Samsung Galaxy phone (as it will be on all Android devices). As you have already said the OP is comparing a much higher spec device with a multicore processor with an older underspecced tablet.

The latest version of YouTube allows you to locate a YouTube video and in one press of a button to another suitable device on your home network. In my case this includes a satellite receiver, a Blu-ray layer and my Panasonic TV.

Saw a tablet advertised on ... was it qvc ....?
that could project the pic onto a white screen
or white wall
.... maybe projecting TV and the Internet is the future ?

My tablet and my phone are both equally as good
at doing the same thing,be it video, music whatever.
Obviously the tablet has a bigger screen but the phone
is always with me, so they get equal billing from me!

No difference between my 2013 nexus 7 tablet & my nexus 5 phone, when it comes to playing videos on you tube. Both excellent and uninterrupted.

OP doesn't say what type of tablet he's got.

Or what phone

Generally, a tablet has a bigger, easier to see screen. Better suited to longer term use. May also have a bigger, longer lasting battery.

In the op comments it sounds as if the wifi antenna built into that tablet is inferior to the one inside the smart phone.

As you don't say which sony smartphone you have, it might not work, but on a Xperia Z1,:
1: find a piece of empty desktop
2: hold your finger still until a menu appears at the bottom
3: tap "widgets and apps"
4: tap "Shortcuts"
5: tap "Bookmarks"
6: select the site you want to add to your desktop

its a Gemini tablet

the smartphone is a Sony Xperia

Thanks for the tip
I did just that and got to a bookmarks page
... empty of course !
The trick now is to figure out just what to hit
when Im on a site like U tube....
one of those tiny icons at the top that I can hardly see, must be a bookmark icon !