What is the difference between these two rams?

[Miloking101]

What is the difference between these two rams?
Corsair Vengeance CMZ8GX3M2A1600C9 8GB (2x4GB) DDR3
Corsair Vengeance CMZ8GX3M2A1600C9R 8GB (2x4GB) DDR3
Also what are some affordable 2x4gb ram for gaming?

 

[manofchalk]

The 2nd ones red, thats all.