I've heard many different opinions and the last was that you must keep the fans at 100% and this will extend the life span of the gpu's. I run my fans 70% and the temp is around 82c and you could not touch the cards.They're extremely hot. But i think my problem is not from fan adjustment instead of space ventilation. I have placed too many gpu's in one room and have no option to put some king of fan to get our the air. Do you think this temp can cause some damage to the cards - evga 1070 ti.
Cheers!
Most fans used in GPUs don't handle extended time at 100% - the BALL BEARING ones might last a while that way, but far too many GPU makers have moved to cheap sleeve bearing fans that won't last 6 months at 100% and might not last 6 months even at 80%.
Wear is NOT linear with speed, it's more of an exponential function - that last 20% generates MORE wear on the bearings AND SEALS than the first 80% in most cases.
Also, that last 20% generally only adds more like 10% or so to the airflow, normally not worth the wasted power much less the added wear.
CASE fans, especially non-PWM types and anything Rotron/Delta/YS Tech/NMB (couple more I'm forgetting at the moment) ARE normally designed to handle 100% fan speed for extended periods of time.