It is not clear where Bits and Chips  got its information, but it claims AM4 will have 1,331 pins, which is a big increase over the 942 pins on the AM3+ socket. The package will be square, and 40 mm in length, making it about as big as a current socket FM2+ package. It will have a pin-count of 1,331 pins, a big increase from the 942 pins of AM3+, and 906 pins of FM2+. AMD could continue to develop LGA sockets for its multi-socket capable Opteron processors based on the "Zen" architecture.
The AM4 platform layout will be functionally similar to the FM2+ than the AM3+. Besides the integrated memory controller, the northbridge will be entirely located on the processor die. This means that the HyperTransport main system bus will be wired internally.