GDDR4 could have been a smart move as it is much more power efficient than GDDR3. Those 16/14 chips of GDDR3 on GTX280/GTX260 are going to suck stupid amounts of power, something like freaking 60-80W for the GDDR3 alone...
65nm - instead of 55nm - is another problem and causes more unnecessary power consumption.
And yet again, nV fails in creating a practical PCB layout. The board used for GTX280/260 is pure horror.
You were not supposed to see this.
Suum cuique pulchrum est.