AMD revealed that the pair of 8-core "Summit Ridge" dies that make up the Ryzen Threadripper multi-chip module are heavily binned. AMD hand-selects the top-5% highest performing "Summit Ridge" dies for Ryzen Threadripper manufacturing, which makes these chips of a higher grade than even what AMD sets aside for Ryzen 7-series socket AM4 chips. AMD requires the highest grade "Summit Ridge" dies to use in Threadripper chips, to keep electrical leakage to the minimum, so the chips can run as cool as possible, with the least power-draw. Choosing the best dies could also ensure that Threadripper chips have the highest overclocking-headroom taking into account other electrical and thermal constraints. A 7-series chip such as the 1800X could still achieve higher clocks than a Threadripper chip, in that sense.