PCB 7970

Well typically a PCB has different sizes in length so I'll take a look at the 7950 stock card and compare it with the stock 7970 card from Sapphire. I would say they are about the same PCB wise they are both based on the same core Tahiti so its very likely they don't have a major difference PCB wise. On the Nvidia side its a bit more noticeable the 680 has a longer pcb then the 670/660Ti.

Card Dimensions
11.42" x 4.92" x 1.38"

Card Dimensions
11.02" x 4.72" x 1.57"