I would rather spend my money on more memory than faster memory. Also with the price of memory the way it is now, I would not even bother with 2Gb sticks. 4Gb sticks would be the way to go. Like kilo said, generally speaking, 2x4Gb memory kit will be more stable especially for OC, than 4x2Gb sticks.
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MSI P55-GD65 with i5-750 @ 4.0Ghz vcore 1.370
Xigmatek Balder HS/2 120mm fans, Antec EW PSU EA750 750W
GSKILL Ripjaws 2x4Gb DDR3 1333
One 2Tb Seagate LP, two 1.5Tb LP Seagates
Gigabyte GTX 460 1Gb OC to within an inch of it's life
Lite-On 24X DVD burner, LG 12X Blu-Ray burner
COOLER MASTER Storm Scout
Win 7 Pro 64
Lots of fans spinning with little LED lights blinking
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