^ Different architectures u cant compare clocks.
Anyway 480 was loud as hell and alot of ppl where happy with it. Also it was a toaster along with 470/465 and alot of ppl bought it. Nowadays alot of OCNers are recommending a used gtx480 since its cheap. So in reality temps/noise is moot.
And as alot of ppl said even if it clocks to 900mhz, when ocp hits its useless. The card is limited by pci-e power (period). You want to buy a gtx590? i suggest waiting to see if non-reference designs are in the future. Or a revised edition/batch of the card.
The main concern is that even if u watercool the card, u cant get rid of ocp. As soon as the card starts consuming alot of power, ocp kicks in even if the temps are fine all over the pcb :s. So u have to disable ocp, and thus increasing ur chances of frying the vrm, even under water, aka 570s. Its just messed up really. Gtx6xx/HD7xxx series am waiting .
Edit: Also since the card takes much power, it might hurt the mobo itself. Someone with 1500 silverstone strider psu, had a 590 burnt. He didnt overclock, the guy had launch returned back turned his pc on, boom the whole thing fried and took his mobo with it. If you dont have extra power to ur pci-e slots, i suggest little to no overclock.
do you have a link to this? and also how do you add extra power to your pci-e slots?