you can't just overclock a cpu dude , come on don't you know this by now !
Besides the Durango isn't a jaguar cpu
If you're prepared to eat into yields then you can alter clock speeds without even having to redesign power supply and cooling and make a final decision shortly before beginning production. And if your planning is good then having the option to draw and dissipate a few more Watts 12 ~ 18 months out needn't be such a huge deal.