Extremely loud at 50% fan speed? Well i think everyone has a different definition of "loud", i cant hear them over my case fans. Only if i put them to 60% i can hear them.
They reference coolers are best for multi-gpu setup, since they blow air out of the case, non-ref cooler blow air in the case making the other cards& cpu heat up more.
I have 9 case fans installed and my GPU fans running at 50% all the time and my PC is silent... Literally silent. You can't hear anything unless you get really close to it and listen very closely.