As can be observed, these are both 2 x 4GB sticks and are pretty much identically priced.
G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory
(http://uk.pcpartpicker.com/part/gskill-memory-f312800cl9d8gbxl)
---------------------------------OR------------------------------------
Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory
(http://uk.pcpartpicker.com/part/corsair-memory-cml8gx3m2a1600c9b)
G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1600 Memory
(http://uk.pcpartpicker.com/part/gskill-memory-f312800cl9d8gbxl)
---------------------------------OR------------------------------------
Corsair Vengeance 8GB (2 x 4GB) DDR3-1600 Memory
(http://uk.pcpartpicker.com/part/corsair-memory-cml8gx3m2a1600c9b)