you probably have a bad contact TIM from the die to lid and the only real way to fix it is to delid it(which voids warranty). ivy bridge and haswell used TIM instead of Solder for the lidding process so in cases, chip cooling efficiency has greatly decreased, assuming you are using you installed the unit correctly.
I fear you may be right. Though I have noticed the Corsair mounting system is pretty crappy, the mounting bracket that presses down on the block rests on 4 screws, and I'm pretty sure the bracket is touching the top of the posts on those screws, so no matter how hard I tighten it, it doesn't make proper contact.
I can't really say if thats right though, it seems to be on there pretty solid, and when I take it off, theres a good circle of TIM.