Preparing The GeForce GTX 1080 Ti For LN2
Now we're talking about extreme overclocking. Hopefully, you're ready to put some effort into preparing the hardware. Good work here is the key to success later on.
Waterproofing
We've covered the steps to overclock CPUs under LN2 multiple times; the same principles apply to graphics cards as well. If you'd like a little more background, check out De-Lidding and Overclocking Core i7-7700K with Water and LN2.
Unlike the top side of a motherboard, graphics card PCBs typically employ a lower profile; there are fewer tall components, making the on-board hardware easier to isolate. My favorite method for sealing everything off involves wide adhesive tape and kneaded eraser. It's quick to apply, easy to remove, and watertight.
You'll want to lay down long bands of tape on the areas in need of protection, and seal the boarders with kneaded eraser to keep water from seeping in. The straight sections between the capacitors and coils are filled with absorbent paper towels (blue). Don't try shoving eraser in there. While it'd be easy to apply, removing it would be almost impossible.
There's no need to protect that area to the right of the VRMs. It warms up enough during operation that the PCB remains at a positive temperature, and therefore avoids forming condensation. Just be careful. If the card is powered off for too long with LN2 applied, this barrier won't keep the board warm.
The back side is even easier to protect.
In the image below, you see all four of our waterproofed test samples. Don't get distracted by the colors; this is just from using different rolls of tape to prepare the cards.
The first six GeForce GTX 1080 Ti Lightning Zs we prepared were for MSI at Computex 2017. Our method proved successful at the show, and nobody complained about how they looked. By repeating our process, these four cards only took an hour each to get ready.
Over the years, I've developed a technique for protecting GPUs that involves a lot of tape. You probably already know the golden rule of engineering: if it moves and it shouldn't, use tape; if it doesn't move and it should, apply WD-40.
GPUs dissipate massive amounts of heat. Imagine 1000W, the power of an electric space heater from one meter, but concentrated on a surface measuring hundreds of square millimeters. Not surprisingly, the cooler pot installation process is absolutely critical. If the pot isn't positioned correctly, you risk a poor overclock or, worse, damaging the GPU die. In order to ensure the pot is fastened securely, we add layers of tape around the GPU. You need enough so that the pot touches the tape before it touches the die, but not so much that you end up with a thick layer of thermal paste inhibiting heat transfer.
Our Power Mod
These cards have sensors that ensure power consumption never exceeds a certain wattage. If that limit is hit, the clock rate scales back as a protection mechanism. But with the right tools, this limit can be deactivated, or at least raised high enough that it'll never be reached.
In order to trick the sensor, simply solder a wire between its input and output. This effectively blinds the sensor, which will no longer send an alert.
In the following image, you can see solder marks near the eight-pin power connectors. During our tests with LN2 and the extreme BIOS, we modified two of our four cards and never saw their frequency drop. It may seem like such a modification isn't useful. But for a card with its warranty already voided, you may as well do it and ensure that clock rates never throttle.
Capacitor Mod
A lesser-known cap mod involves adding capacitors, which help smooth voltage. A more stable voltage enables better overclocking.
While adding capacitors isn’t particularly difficult, pay attention to their polarity markings. Reversing the polarity can end with smoke or a pop. Also, choose components with the right voltage, capacity, and tolerance. Your soldering work should be clean, and the capacitor legs need to be trimmed as short as possible.
For certain older or entry-level cards, this mod can sometimes help. But a crummy power supply with a cap mod still leaves you with a crummy power supply. The capacitors won't work miracles.
In the case of MSI's GeForce GTX 1080 Ti Lightning Z, we didn’t see any benefit from adding caps. Then again, the factory power supply is solid, and it didn't limit our overclocking efforts in any way. Thus, it only made sense to test one of our four samples with this capacitor mod.
Voltage Check
This is what we call easy prep: take the connector and plug it into the card. All done! Really, though, these connectors are great for hooking up a multimeter for observing supply voltage to the GPU, memory, and PLL.
BIOS
MSI's card has two available BIOSes and a switch to select between them. So, we updated the secondary firmware with a special version provided by MSI for extreme overclockers. Without this BIOS, some of Afterburner's functionality won't work (the Power Limit can't be raised very high, for instance).
Installing The Cooling Pot
The last step before starting our tests is installing the cooling pot. It must be secured to the GPU. At that point, we're able to start pouring liquid nitrogen into it. This cools the pot, chilling the GPU underneath.
Given that the pot is relatively heavy (nearly 2kg), it must be positioned correctly in order to avoid damaging our card. A plate, some screws, and nuts are used to hold the assembly in place.
It's important to use the correct amount of force when tightening screws. After all, you can exert hundreds of pounds of pressure on a single point without even realizing. To avoid bending the PCB or desoldering the GPU package, we use a backplate for reinforcement.
At last, we catch a glimpse of our completed installation. The top pot cools the GPU, while the one on the bottom sits atop our host processor. The fan on the left side of the image cools the VRMs.
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