One module is about 45mm high with heatsink, 92mm fan.
Much higher OC would be possible with the 10 Chip version because it can supply the whole 60 Amps to 10 chips.
At 450Mhz the 20 chip modules are already close to the power limit of the voltage regulators .
Probably already exceeding the 60 Amps design spec but with good cooling they should be able to push up to 80 Amps.
The upper voltage limit is 1.8 Volts

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I thought the overclocking test was done with a fully assembled board and the production voltage regulator. So is it possible to run a bitburner XX at 450MHz and 1.3V?