From Tom's Hardware:
"Nevertheless, in a comparison between GeForce GTX 590 versus Radeon HD 6990, Nvidia wins.
And it wins because I can put a GeForce GTX 590 in my workstation, which doubles as my gaming machine, and not hear it. It’s quiet enough to use. And that’s a requisite.http://www.tomshardware.com/reviews/geforce-gtx-590-dual-gf110-radeon-hd-6990,2898-19.html
From Hardware Canucks:
"The GTX 590’s real accomplishment is the feeling of refinement that it exudes. Unlike the HD 6990, its VRMs don’t squeal like a scared piglet
and fan noise is kept to an absolute minimum. The fact that its svelte 11” length will fit into a wide variety of cases should also make it in vastly more appealing than the behemoth AMD is currently saddled with."