Question. Are all the corsair sticks same revision? I came across a similar problem with 4 1gb corsair dominator sticks. Two were rev1.2 microns and would go beyond 1250mhz, and the other two were rev5.1 garbage they wouldn't even run more than 1080mhz.

It sounds like you have two different revision sets, Micron ICs need lots of voltage and you might find if you have a pair of rev1.x and rev4.1 or rev5.1 thats the problem. Rev4.1 and Rev5.1 don't like much more voltage than they are rated at. Where as Rev1.x Microns crave voltage like you can't throw enough at them.

Have a look at the sticks because it sounds like this is your problem in my experience. Also if Prime blend is failing you have Vtt or GTL related problems, nothing to do with memory. Different straps and dividers require different sets of values. 1:1 divider works great with 1gb sticks but runs like crap with 2gb sticks, and needs way too much Vnb. I had 4x1gb running on mine a while ago and managed to run them out to 1190mhz with some playing around so this isn't a problem at all.

RF runs 4x1gb fantastically.