I have increased the fan speed and found something I don't quite understand.
With the factory settings, whenever my gtx570 would reach 84/85c and 63% fan speed I would hear a loud fan noise (kind of whoooooooo) which I believed to be the vga fan trying to coold the GPU
I have set the fan speed at 70% and found a dramatic decrease in temperature, from 85 to 72c at full load, which is good. However, when the vga fan at 70% reached around 2800/2900rpm it was relatively quiet. Doing a different test i found out that the loud fan noise was in fact coming from my CPU fan (stock) whenever it reached 70c at 2600-2700rpm.
What I'd like to know is, when my vga card was at 85c, fan at only 63% (seemingly not enough to cool it to a lower temperature) my CPU would also heat up and therefore increasing its fan speed, giving me the loud (whooooo) noise, but when I increased the vga fan speed reducing the temperature from 85 to 72 the CPU temperature also stayed down without the fan rev. up to loud levels. What is the connection between the GPU and CPU? Why would one influence the other, is it just a question of temperature within the case and the proximity between vga and cpu-fan that sucks in hot air, or is it a question of shared workload? Is this normal?