By themselves, no real world performance difference whatsoever.
However if you look at the bigger picture, DDR3 RAM basically means you can use Core i5 and Core i7 CPUs. Now those CPUs will provide a performance increase depending on what exactly you're doing with the PC. Old C2D/C2Q CPUs do not benefit from DDR3 RAM at all.
There usually isn't so much of a difference between one generation of RAM and the one before it. It's just the evolution of the technology in the bigger picture. RAM speeds have gone up and power usage has gone down.