Outside of GGG, probably Martinez. Martinez can really hit and it shows seeing how he's dropped/KO'd numerous people with 1 shot and kept Chavez Jr very honest with his power.
This is just from word of mouth and I don't like Son Of A ***** but from what I've heard he packs a heavy punch. Like it's not his style to focus on power but when he does apparently he has demolishing power. It's on interviews from people who've sparred with him and seen him in the gym.
Fuk i hate that nickname why wouldn't they try to give him a different one Kid Chocolate belongs to a fighter who has already fought... :verysad
Can GGG match the power of the punch that landed on Williams? I'm not sure Golovkin and Martinez are in a league of their own in punching power at middleweight
Sergio and Golovkin has different type of power. Sergio shots are very fast and catch people while coming forward thus creating the devastating effect. Williams never saw the punch for example. Golovkin is very very heavy handed and even if his opponent is able to see his punches even his jab hurts like a power punch.