It's an L4, full Batch# L420B788
I'm doing 4.2@1.16v in bios. HWiNFO shows volts to be 1.176 under load. This keeps load temps under 70c even on my modest HSF.
I may be doing something wrong, I'm new to Haswell, but so far overclockability is not great. 4.6 is a no go at 1.28v, won't boot to windows even. 4.4 appears to need at least ~1.24v
It could even be that you're relatively "new" to OC enthusiasm -- I couldn't say. I don't find any reason to think it -- either way.
But the info on this first batch of i7-4790K chips is starting to coalesce around a fuzzy view of it.
Some guy posted his thread on his entire 4790K project of things he didn't even hesitate to do from the start: among other things, he delidded it; he replaced the "new" polymer-TIM with CLU, and I don't even think he thought to get a bench basemark with the factory TIM. He deployed what seemed to be a rather refined custom water loop.
He was able to try settings toward 5GHz. But (my recollection) he topped out at about 4.8Ghz. At that point, he was pushing the voltage toward 1.45V, and the load temperature was about 69C.
So if Intel promoted the chip with info about "additional capacitors, [etc.]" enabling better OCs, they balanced their warranty-cost-benefits and reputation against increasing the base clock speed by 500 Mhz with the same Turbo spread to about 400Ghz above that.
I'm more inclined to guess that they OC'd and binned their own processors -- a continuation of Haswell.
Given that this is a "haswell-refresh," we could speculate over what's in store with the "E" release. Since Intel disciplines its pricing with ease because it is something like a duopoly, dominant firm or similar company, they'd have no reason to jettison the indium-solder fabrication process to shave a few pennies off Haswell "E" prices.
I wouldn't have expected any earthshattering breakthrough with Haswell-E, either. It just continues in my "promising project" inventory at the moment, with the trust that Intel will continue to use indium-solder as they had for SB-E and IB-E before.