Originally Posted by Blameless
Of course it's going to eat into headroom. That's what the headroom is there for...to allow for rapid adaptation to market needs. Intel clocks their parts as low as they can get away with, so if they get caught by surprise they can show up with an SKU that's several hundred MHz faster overnight and wow mainstream reviewers.
There is certain stuff called wearing out of CPUs. Intel don't wanna degrade theirs CPUs by overclocking, and Intel doesn't like to distribute high end heatsinks with theirs CPUs. In fact, one of Intel's advantages is energy efficiency in comparison to AMD.
Intel clocked 4790K close to the limit, and it caused problems. Actually it caused massive problems, when normal users used normal heatsinks for non OC work. High end overclockers delided and didn't notice, but when you look at HW seller pages, and forums, you'd see lot of posts when users received CPU that had problem on normal clocks.
Headroom is there to ensure durability. Removing headroom would only cause problem to end user, and to Intel. Intel is trying to reduce durability problems by using certain internal stuff on SKY, to ensure longer durability by playing with power. But playing it dangerous might hurt Intel's sales and Intel's reputation.
Frankly when Intel would use full headroom, I'd do underclocking.