It doesnt in Cinebench at least. Here is an article on memory speed/scaling.
http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/5
EDIT: I do believe things like compression do show results with faster memory.
http://www.anandtech.com/show/4503/sandy-bridge-memory-scaling-choosing-the-best-ddr3/5
EDIT: I do believe things like compression do show results with faster memory.