Corsair XMS2 vs Gskill 2GB DDR2 PC6400

[Jetpac]

Which ram for a conroe E6300 system that i am going to overclock
i can get a 2GB (1GBx2) set of each for about the same price.

which is going to give me the best performance / be most stable

also i can only afford the PC6400 with cas 5 latency unfortunatly... is this a big step down in performance from the CAS 4?

Which one should i get?

 

[Jetpac]

i will be using that exact board.

well im in the uk and prices are slightly more expensive :S
if i was us i would have jumped on the gskill Cas 4 offer

but as my options are limited:
should i go with that or go for the slightly moreexpensive corsair

gskill CAS : 5-5-5-5-15
Corsair CAS : 5-5-5-5-12-T1.

gskill: £135
corsair £146

howver i have just found some

Geil Ultra CAS 4: 4-4-4-12
£152

or Ebay for some OCZ Platinum at £156
(numbers taken form the relevant items at overclockers.co.uk)

any more input greatly appreciated