Quite frankly, if you're buying RAM, you're either gonna run it at stock speeds, or you're gonna be striving for a 1:1 ratio with your FSB as you overclock your CPU. There is no half way pitstop, it's either one or the other.
Frankly, XMS as far I am concerned is expensive value RAM, you sure as hell won't see it hitting 300MHz, it doesn't like as much vDIMM as other chips, and it simply can't keep up past 250MHz. As far as value RAM goes, I could care less what you purchase so long as it is not low latency TCCDs or something ridiculous like that. Waste of money.
Anyways, all I'm getting at is Corsair aren't made to overclock, and can't hold a candle next to Patriot, G.Skill, PQI or OCZ.
You're going overkill getting expensive XMS low latency chips to run stock speeds with no real world gains over value RAM, and you're putting the last nail in the 1:1 coffin if you buy this stuff and want any decent overclocking results.
It's not because I hate it, it's because it's been stastically proven that A) low latency memory has little to no effect on bandwidth and B) Corsair cannot overclock if their life depended on.