Chael did not have a knockdown. Anderson's hand touched the mat, but this is MMA, not boxing, and fighters know that they can go to the ground without getting a standing 8 count and an automatic 10-8 round. He barely touched the mat to help him regain his balance, whereas Chael got knocked on his ass when he went down. Either way, even if you consider what Chael did a knockdown, it's clear who's was more effective.
And when you punch someone 320 times and they have hardly any marks, that means soemthing. Anderson got Sonnen to duck his head down with a punch from GUARD. That's the whole reason he was able to set up his triangle, because Chael couldn't handle getting punched from guard. lol. Then there's Anderson, who let Chael hit him a number of times, including the "knockdown", as you call it, where he had his hands down by his side. So you tell me who's strikes are more effective.
A) It counts as a knockdown.
B) Chael outstruck Anderson in the first fight.