I have one in my son's SX1000 case and I think it's pretty quiet, but am not sure. Next weekend I plan to put a baybus in to slow down the four Silencers, and then I will know better. When I did that with my SX600 (with an Enermax 365VE(FC)), it became clear that the PSU was a lot louder than I had thought. I was thinking about either swapping in my son's PSU or trying a Zalman.