Which corsair to go for?

[hyper_piper45]

I am going to be getting the ds3 but im undecided on my ram. The choice is between,

Corsair 2GB DDR2 XMS2-6400C4 TwinX (2x1GB) (MY-108-CS)

and

Corsair 2GB DDR2 XMS2-6400C5 TwinX (2x1GB) (MY-092-CS)

My basic question is if it is worth the extra money for the C4?

Will i see a big real world performance increase or is it unnoticable in normal usage.

Thanks!