Preparing The Motherboard
Measurement Points
We begin with a little modification to the motherboard. Test points are available on the PCB, but Asus sadly neglects to include connectors. As a result, it's on you to precisely touch the indicated pads with a multimeter in order to take measurements.
Normally that's not an issue. But when it comes to extreme overclocking, voltages have to be watched more closely and we don't always have our hands free. Right away, we add something to plug our volt meter into for easier measurements.
LN2 mode
Some preparations are easier than others. In this step, we simply move the jumper labeled “LN2 MODE” in order to activate it. Once enabled, the motherboard automatically starts up with higher supply voltages. This will offer better support for the extreme conditions we're planning to apply. Certain hidden profiles in the BIOS are also unlocked.
Don't enable the LN2 MODE jumper if you plan on overclocking at ambient temperatures. Following the activation of this mode, the PLL (Phase Locked Loop) will transition from 1.8V to 2.1V. If you read our previous article, we revealed that raising PLL from 1.8 to 1.9V caused an 8°C temperature increase. Raising the PLL to 2.1V on air cooling should be avoided!
Isolation
When overclocking with liquid nitrogen, special care must be taken to protect your hardware. Ice will form and you don't want to risk water droplets falling onto the electrical components. We presented a number of ways to approach this in De-Lidding and Overclocking Core i7-7700K with Water and LN2.
To start, we remove the heat sink covering the motherboard's VRMs. This step isn't obligatory; it most depends on the overclocker's preference. In our opinion, though, this sink is useful for extreme overclocking, so we prefer to take it off. This facilitates the insulating steps that follow, and even more important gets rid of a big metal mass. That could be a big risk for forming condensation otherwise.
Once we're down to the bare motherboard, we craft a “shield” made from shop towels. This protective layer must be fitted as tight as possible in order to prevent condensation from reaching the PCB.
Unused RAM slots are filled with towels. The space between surface-mounted components gets the same treatment, too. To finish, a section of neoprene is fitted around the socket. This protection serves as a last defense, though we hope that condensation is stopped well before this stage.
If it is properly made and placed, this ultimate protection is sufficient to shield the hardware without damaging it, and can be easily removed. Once the cooling pot (which holds the liquid nitrogen and cools the CPU) is in place, we pack on more shop towels. The pot is wrapped in neoprene, then towels, and any exposed portions of the motherboard are covered with several more layers of towels.
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