I think overclocking is going to be extremely limited, with four TPS53355 per board, or one for 16 chips. On the S1, it's one for 8 chips.
Thats the detail I've been waiting for
*really hoping for a PCB photo still*The S1 could consume around 45W per group of 8 chips overclocked (overclocking pushed the regulator right to its limits, but the real limiting factor was the voltage being set to 1.1V - some people have apparently pencil-modded the S1 to almost 215GH/~470W, or about 60w/8 chips)
45W/1.1V=40.9A on a 30A-rated component. (bitfury h-boards faced very similar amperage limits when overvolted around 0.95V)
Its likely these chips run at around 0.8V and 1000W/640chips is about 25W per cluster of 16. That leaves a LOT of headroom on the regulators, but some of this is lost to the difference in voltage (more amperage). 25W/0.8V= 31.25A stock.
Presumably these should be able to overclock without any issues from the regulator. I imagine all other components are beefy enough also. I imagine you will hit hardware errors at 15-20% overclock as with the S1. These may even be capable of up to 1.5TH is voltage was increased to ~0.9V
I'm quite sure those puny heatsinks will not be enough when overclocked, 200Mhz+ will fry the chips unless some hefty cooling is applied!
If you want to overclock the BM chip, the S1 was made just for that!!
one way to add more cooling would be to replace the thermal paste with some geld extreme .. this will also reduce power consumption . copper heat sinks would probably work good as a replacement. i used copper heatsinks on the ram chips and replaced the thermal paste with geld extreme on the gpu's in my r9 290'x's ... any idea how big are the chips underneath those heatsinks ?? this trick would probably work on the S1's too .