Neither Blender 2.62, 2.63 nor 2.63a can use the OpenCL rendering with Cycles. It begins with trying to compile the shaders which takes maybe 1-2 minutes then seems to end without really rendering, thus still displaying only a black screen. Repeating it several times has the same effect and result. Cycles rendering with CPU works well though, but very slow.
I tried LuxMark v2 to test if my card can in fact compute OpenCL and it worked flawlessly and compiled the shaders in under 1 second and rendered with its 24 compute units as it should.
