My high school was similar: I wouldn't say all the popular kids were smart, but I'd say that the distribution wasn't skewed the other way either.
And I didn't see much bullying in high school, though it happened a bit. I do remember kids bragging about having made so and so cry, and me getting in to arguments with them over it, but generally people were pretty cool to each other in my high school (and I was pretty low on the popularity-scale, so I'd know). In junior high and particularly elementary school, though, it was a very different story.
When I was in 5th and 6th grades there was one kid in my class that was tormented horrendously. It's still one of the things I feel most guilty about to this day that I did very little to help him. I at least didn't participate in his torment. But when the kids in my class (it was not anyone in particular, but everyone) blamed every thing that happened on him: "Who said that!" says the teacher, "Justin!" says any one of the students in the class. At which point the clueless teacher hands down another punishment on Justin who, once again, has done nothing wrong.
And when the teacher wasn't there? "Hey, Justin, isn't that the same shirt you wore yesterday?" Asks one of the girls in the class. Everyone laughs, and then the next person comes in with "He's been wearing the same one all week." "Don't you notice the smell, Justin?" Etc.
I don't remember much physical violence, though he certainly got tripped in the halls a lot. But the torment was constant, and it came from almost everyone. I hated myself for not stopping it. For not calling my friends on it when they talked about him behind his back. But I was terrified that they'd think I was his friend, and that I'd thus become him.
He went to a different junior than me, and most of the kids in my elementary school, and I hope things went better for him after that.