A while back, we got a clue that Socket AM4 would use a new heatsink mounting system when be quiet! announced it would be giving away free mounting kits for its existing cooling gear. As it happens, the AM4 mounting system is similar to that of AM3+ (a system that traces its roots back to the Socket 754 era), but the AM4 backplate uses slightly larger dimesions. Overclock3D got a few pictures of the mounts and confirmed those larger dimensions. Most existing heatsinks and waterblocks aren't going to fit the new socket without a new mounting apparatus. Happily, a handful of heatsink manufacturers have now posted information about their approaches to AM4 compatibility for customers who already own aftermarket coolers.
Cryorig's AM4 mounting system
Noctua, Phanteks, and Cryorig have joined be quiet! in offering free cooler upgrade kits for Ryzen CPU coolers. Cooler Master takes things one step further and says that the latest shipments of many of its existing products should fit Socket AM4 motherboards. Builders who already own the Hyper D92, the Hyper412, the Hyper612, the MasterAir series, the MasterLiquid Pro series, and the Nepton and Seidon water-coolers will require new mounting hardware for Socket AM4, however.
Noctua's AM4 upgrade kit
Folks with AMD stock heatsinks like the Wraith won't need new mounting hardware, according to TR's conversations with the company at CES. Enthusiasts looking to upgrade to Ryzen likely have an aftermarket cooler or two floating around already, however, so it's nice to see that many companies are stepping up to the plate and providing builders with a way to mount their existing hardware to the AM4 socket.