RAM upgrade for my new X51 R2

[freestyledom]

Hi, i just recently bought a brand new X51 R2 with 4th gen i7-4790 and gtx 760ti 2G . (http://www.dell.com/sg/p/alienware-x51-r2/pd?ref=PD_OC)
and i want to upgrade the RAM to 16G (2x8G). waht i want to know is which is the best ram to get (for example the Corsair Vengeance Pro Series or others) and what's the max MHz of the RAM my system can support? thx!!

 

[SWAT_Glock]

I would put the same MHz that is in there now. I never seen a difference by bumping up and using a higher ram chips other than on paper. EX: 1600mhz vs 1800mhz. Just make sure you do not get ram that have giant heat sinks or it may be a real tight fit. I never had a problem using Corsair or Kingston memory. Samsung memory is decent too.