Passive cooling tdp to rad size

[graydust153]

Iv got sli 1080ti with a 5930k when I originally I thought it was going to be much quieter with the amount of rad space. I was trying to get the system to be able to passively cool.

The question is how much rad space should you have per 100w if tdp if you wanted it to be passive

 

[dederedmi5plus]

the idea is to level the temperature from cold plate (GPU + VRAM + VRM direct contact plate) to hot plate (aluminum fins), the question is how fast room temperature (25 deg C) cools the fins or any kind of surface. Doing as you posted require wide surface area, there're passive cooled PC case (the cold plate is channeling heat through heat pipe and uses case's body as heat exchanger) but would be hard to buy.
All GTX 1080Ti PCB design (NVIDIA reference PCB, tall PCB [ASUS Strix, EVGA FTW etc], and non reference) comes with hot VRM that also need proper active cooling, AFAIK no passive cooled case designed to cool both CPU and GTX 1080Ti.

AFAIK BeQuiet silent wing 3 fan offers noise to performance ratio better than other fan on radiator, you can cool GPU with liquid nitrogen + EKWB GPU waterblock + EVGA GTX 1080Ti K|NGP|N

 

[zebarjadi.raouf]

First off, it's not that simple. You have to consider airflow, rad size, room temps, .... You will also have noise because of the pump + PSU. I have four ideas right now:

1. Use soundproof/isolated case instead.

2. Add a small Peltier + small passive heatsink on top to cool water. Should compensate for the lack of fans. Requires a little modding experience

3. Use fans below 20dB. Should be barely audible.

4. Use headphones or longer cables with the case further away.
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1080ti SLI + 5930K = 300Wx2+200W=800W
As for the main question, with good airflow inside a cool room, minimum should be a thick 360mm for passive under load. More is better.

 

[rubix_1011]

Watercooling has never really meant to be a fanless/passive system simply from the design of watercooling radiators themselves. Radiators are compact and densely packed fins and tubes that really need airflow to benefit from displacing thermal load using coolant.

As mentioned above, even low RPM fans can make a large difference but passive likely isn't going to be easily accomplished. This is why fans and setting fan curves using PWM controllers is probably a better option.