i have sapphire HD 7870XT Dual-X. both fans was spinning in the first two years from buying the card. after that i started to notice that the second fan doesn't spin unless fan speed at 78% or above. i guess it happened after i installed Crimson driver. but that doesn't matter as i get used to it, and one fan seemed to handle the graphics card.
what is matter that after a couple more years and after i replaced my old thermaltake 450w PSU with FSP Hexa 500w, i've noticed that even the other fan doesn't spin at idle unless temps are above 42c (48c now). and the moment i stress the gpu with furmark or with a game it goes down instantly to 0 RPM (i don't know why?) until 78% then start to ramp up again with the other fan. suddenly from 0 RPM to 3000's RPMs!.
even with the fan curve set it to ramp before 78% it doesn't.. thats in gaming or stressing only, which is strange.
i can ramp it up before 78% but with no stress on gpu. and it will turn itself off when temp is at late 30's or after a few minutes at idle.
i just need any explanation for why the moment i stress the gpu the other fan that used to work all times goes down to low RPMs until its 78%?.. and why it doesn't spin at idle unless temp is above 42, then when temp decreases to mid 30's the fan turn off again, and so on..
i haven't installed any new third party programs before that happened and i haven't installed any new drivers.. the cause seems to be deeper than just "faulty fans". because if it just a dying fan it will act randomly. but it seems that its being controlled by something. although this issue happens in the bios.
Edited by whiteknights, 18 November 2017 - 02:20 AM.