How loud should GPU fans be?

[Scouse]

Got my new 7870 running at full pelt so the fan is currently on as high as it goes.

It's pretty silent when it's not being hammered but whilst it is there's an audible, throbbing, buzzing sound that comes and goes in waves.

Is this normal?

 

[ECA]

Yup.

 

[Aada]

My GTX670 fans only run at 63% when at max usage temp hits about 70c

 

[Scouse]

Yup.

It's f00king annoying. I always thought they were supposed to be pretty quiet.

 

[ECA]

How airventy is your case? my 6990 in a non windowed non case fanned case is "ok", in my "open" case it's noisy as a motherfucker.

 

[Scouse]

It's a nice big old case that houses 4 HDD's and 2 SSD's. It's not the graphics card overheating because of ventilation - it's number-crunching that the GPU is getting through which produces the heat. GPU is maxed out a lot of the time.

Ah well. It's nice and quiet at other times so...