Windows 8 64 bits / GeForce GTX 560 Ti
Blender 2.71 Date 2014-06-25 18:36 Hash:9337574
When using Area light with ray shadow on, there are artifacts on dark side of curvy objects. See attached image and blend file.
1.) Add a sphere.
2.) Add an area lamp
3.) Area lamp > Shadow > Ray Shadow
4.) Render