Build Help: i4670k memory and mobo suggestions

[wakeboarder3780]

Making a new build, here is what I have tentatively decided on:

2 GIGABYTE GV-N760OC-2GD in SLI
i5-4670K
MSI Z87-GD65

I am mainly trying to figure out what RAM speed to get because I understand it is limited / controlled by the CPU. I typically buy OC'able gear but do not OC until more performance is necessary later in the components life. I have not yet had to OC as this is only my second "OC'able" build and my previous one is getting handed down to my wife before OC'ing is needed.

I have heard things like RAM speeds higher than 1600 don't really matter, and a lot of advice suggesting not to get the higher speeds because the cost is higher. I have looked these two comparable items up and don't understand the cost argument:
8 gb of 1600 @ $80
8 gb of 2600 @ $108

To me $27 is negligible assuming I do get a performance increase / OC'ing flexibility. Can anyone help me out? What speed should I get to allow flexibility when OC'ing down the road?

I'm also open to different suggestions on mobo as long as it supports raid 0 and SLI.

 

[ivanjacob]

Ram response time goes down when clock speed goes up so 1600 will be better all around.
Edit: Watch this video: http://www.youtube.com/watch?v=dWgzA2C61z4

 

[STACKS ON DECK]

1600 is enough . . but jumping to 2600 means almost 30% performance boost altogether ..

 

[wakeboarder3780]

Thanks for the responses, I've been mixing in my independent research since I posted the question as well. The real world performance numbers just don't lie. The way I see it now is essentially the only time I *might* see a benefit at all would be when I'm editing / rendering videos that I edit.

I really liked the video you posted, ivanjacob, he delivered a concise message in a likeable format. What he was saying about higher frequencies requiring the tradeoff of higher cas latency is true and something that didn't sit well with me. You can see that even in the links I provided above. With that in mind I have decided to go for the following ram which is 1866 @ 8 CL