I learned not to listen to anyone at Best Buy after they tried to down-sell me to a router that wasn't selling very well. Don't listen to them at all.
I learned this when I was looking for a nice HP laptop for my gf (she wanted it, so yeah).
They had two, virtually identical models except one was C2D based, the other was RM-Turion based. I asked to guy in terms of performance, what I'd see different. He told me, and I quote, "They'll perform about the same, but if it's hot where you live you'd wanna get the Intel, you know, like in Sacramento or something."
This was in the SF Bay Area, and I was just kind of like "Yeah...thanks, I'll keep looking around."
I realize he was trying to be helpful and the AMD cores may run a little warmer, but to make that the up-sell of the Intel model....I don't think so. I later read that the AMD lacks a fair bit of L2 cache compared to the Intel, so that's why it is slower, but whatever