http://www.techpowerup.com/165336/Colorful-GeForce-GTX-670-Graphics-Card-Pictured.html That's one short PCB
PWM worry me the most for a 670 ( so a 680 with one SMX disabled ).. If they have decided to cut pcb, i dont know what could have happend to the PWM .
cheaper to make a card with a shorter pcb. plus, normally directly under the sideblower fan is a vacuum as thats where it sucks the air from, parts directly under the fan generally arent cooled well (think back to the amd hd5000 series, vrms got quite hot).