Raspberry Pi performance?

Hello everyone! I'm planning on getting a raspberry pi for an old CRT and I'm curious about the raspberry pi's performance. 

What I mean by that is, can it play YouTube videos at 720p with no lag at all? Can it also have multiple tabs open at once? I really wanna know. Pre thanks to everyone who replies. 

From my understanding its a pretty basic computer and can handle 1080p. The only thing that should stop you from watching 720p things from youtube is your internet connection.
If you want some system specs, I found some on wikipedia, I know wikipedia isnt the best place, but its all I could find and it seems accurate.

http://en.wikipedia.org/wiki/Raspberry_Pi

It has basic web browsing and multimedia capabilities.  It'll handle HD video and multiple tabs (within reason).  It's not going to be super responsive, even in a very lightweight linux environment, but it works perfectly well.

The pi has similar performance as a pentium 1. It struggles with web browsing and is not optimal for video browsing. It will do it but it will take its time.

Well, now I know what to expect: a decent experience which may be slow. Thanks everyone! :D

You're not going to be able to view youtube videos in the same manner that you're accustomed to, you can't get flash on the Pi, and even if you could, I doubt it would have the horsepower to handle it. Watching videos on the Pi is possible, but it takes a little bit of work.

http://stevenhickson.blogspot.com/2013/04/using-youtube-on-raspberry-pi-without.html

Raspbmc with the YouTube addon. Streams at 720p.

 

http://www.raspbmc.com/

 

http://wiki.xbmc.org/index.php?title=Add-on:YouTube