Out of all the threads I've seen concerning this topic, I don't believe anyone has actually came out and said "why" it's not a good idea to set fans to auto in Afterburner.
Just makes a lot of noise, WHEN U TURN THE GPU FAN ON MAX, and WEARS OUT THE FAN MOTOR, turn your $600 1070 into a brick, maybe this shit was invented by GPU card manufacturers?
Little CPU fan's only cost $3, u want to suck cool air into the front of the card connector and blow cool air down through the cards
I think the idiots, long before they figured out how to over-clock, they first figure out how to control fan-speed, thinking that this was important it became the cause-celibre of mining,
It doesn't do shit, leave it alone,
Just keep your miner under 70C, how do U do that? Keep the power wattage low,
Most important is small cpu front fans one per two cards running 12v, and then have a large 50cm 220v/110v fan ( cost $10 ) at end of cards blowing air over top and bottom of cards, this gets cool air down on the mother board and on the power-supplys
IMHO the fan's on AUTO is best, they turn on when needed
The PROBLEM is that GPU's were designed to have ONE in a box, but when you have a dozen all next to each other they over-heat, the GPU sucking at air in from its neighbor is not cooling thus, U need cool air to be blown in the front, then it rises, the END fans are to direct the hot air out a window, or into a heat-duct
GPU FANS in a RIG don't do shit if they're just sucking hot air from the 80C card next door
But seriously, DRIVES me crazy all these Stupid "HOW to mine" articles and Utube, first thing they do is show 'fan control' BULLSHIT all BULLSHIT
I keep all my 1060's at 65C and my 1070's at 59C, and no noise ever from fans, I blow the hot air out the windows in summer, and let it recirculate in the winter
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Lastly REAL MINERS use linux cmd-line tools to control their GPU cards
WINDOZE is for gamers who stumbled into mining
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10cm front fans (cpu 12v) in front of GPU cards is MANDATORY, and cross fans at end of each rig is preferrable, makes a big difference drops the temp of all cards by 5C, and if you have stacked rigs on a commercial kitchen rack, then the cross fans are mandatory, as you don't want heat from lower right rising to upper rig ( power-supply/mobo)