Bright Side of News came across more photos of the GeForce GTX 670 that reveal how small the PCB of this new card is. This new GK104 based part has a board that's almost half the size of a GTX 680, with two power connectors lined up at the opposite side of the PCI Express slot.
What you are looking effectively is one half of GTX 690 board, and by going this route, the company is saving a lot of money in BOM (Bill of Materials) cost. The power supply components, rear connectors, memory - nothing changed from the GTX 680 and 690. Bear in mind this part is supposed to go against the Radeon HD 7950 3GB, while GeForce GTX 670 will be available in variants of 2 and 4GB of memory.
Given the compact size, don't be surprised to see GeForce GTX 660 taking the very same route. When GK107 chip finally makes its debut on desktop as GT(X) 640, 650, 655 and 660, don't be surprised to see the very same PCB board, albeit with a much smaller chip.