What? It is the 4800+ that's what it's called, it's not 4.8GHz because it's not two 2.4GHz cores working like that so you can't technically consider it working at 4.8GHz at all....it's the equivelant to a 4.8GHz intel, so it'd be pointless to call it a 6000+ since it doesn't perform to a 6Ghz Intel.
As chris said basically, it's to help Intel users although all I've ever seen it do is confuse people. It's at 2GHz (if it's an XP and 1.8GHz if it's an XP-M, this being the 2400+ I'm talking about) but it can do the same if not better performance of that of a 2.4GHz Intel chip.......like I said they do that number so if you don't know of AMD chips, you'll be like "Oh it's kind of like a 2.4GHz intel even though it's 2GHz, I got it...cool!!!!!!"
Of course with a name like FX-55 lol and you just see it's 2.6GHz and costing $800+ I guess you'd think AMD is crap and overcharges when in reality that chip is awesome.
4800+ dual core..........that's just amazing