Why do my renders in Cycles come out fuzzy

I downloaded a build that included Cycles and when I render my image in Cycles it always comes out gray and fuzzy. What am I doing wrong?

Maybe you set GPU OpenCL render and have AMD/ATI video, that combination work with very limited features, no shaders (“clay render”) and other limits. Only NVidia hardware fully supported. You can use CPU only mode, it work on any hardware, but not as fast (4x-25x) slower on average home computer.