How to fix the iPhone 3GS from lagging on videos like YouTube?

I got this iPhone back in January but for a little while now it's been lagging like crazy whenever I try to watch videos like YouTube. I'm lucky to get 5 seconds out if it before it randomly pauses on its own. I have it updated to the latest iOS. If you know how to fix it without jail breaking it please respond.

Clear your safari cache data in the settings http://iphone.pandaapp.com/