Later this year, perhaps in October, AMD will be launching with their highly anticipated Zen CPU architecture. Before that though, AMD will be releasing their new processor socket, AM4, with the Bristol Ridge lineup of APUs. As the socket that finally combines the CPU and APU lineups, it will replace the aging AM3+ and the relatively newer FM2+. According to a leak, AM4 will use μOPGA and support up to 140W chips and have 1,331 pins.
AMD has stuck with variants of PGA for the longest time and it looks like AM4 will continue the legacy. At 1,331 pins, that is a 33% increase over the about 950 pins previous AM and FM sockets have used. If AMD simply enlarges the current design, this would lead to a much larger package. This can lead to more fragile, costlier (especially for lower end chips) CPUs and require a new series of CPU heatsinks.
In order to combat this, AMD has used μOPGA compared to the normal OPGA they use. This will reduce pin diameter, allowing for more pins to crammed together at the cost of weaker pins. Reducing pin pitch or the distances between pins and staggering pins to fit more in the same space are also two likely strategies. For Intel, a 17% pin count cost 30% in space but moving from 115x to 2011 cost only about 66% size increase. If AMD does it well, AM4 may be compatible with AM3+ and FM2+ heatsinks and not have an overly large package.
Finally, AM4 is expected to support up to a whopping 140W TDP CPUs. This is similar to the top end Intel LGA 2011 chips will also feature a 140W TDP and not much more than current mainstream AM3+ chips which top out at 125W. By increasing the pin count slightly, AMD will sport a number close to Intel’s old enthusiasts platform of LGA 1366. By unifying the socket for their budget, mainstream and enthusiasts chips, AMD will make it easier for builders to upgrade, leaving it up to the motherboard vendors to differentiate their offerings.