Vdroop still exists on Haswell board's bios, you missread. Vdroop affects the VRIN on haswell which is what feeds the on die VRMs, which feed and will trickle down to your vCPU.
Yes, but it doesn't mean the same thing, as you just explained yourself. Like you said, Vcore is not longer set by the motherboard, but rather the on-die VRM on Haswell. Instead, the VDroop on a Haswell board can only refer to the VRIN. This is a much less finely-grained mechanism, as Intel has effectively taken that level of control away from the motherboard manufacturers.
So, yes, as an overclocker, you don't quite have to worry about it in the same way. It's out of the picture for you
, because you now have much coarser level of control.
What I was getting at was that it isn't out of the picture for Intel
, and that's what matters. Haswell's on-die VRM is still doing VDroop per core, and for good reason.
Additionally, what I was referring to is more the general tendency of motherboard manufacturers to offer a lot of sliders to adjust various things, many of which are ill-advised and even more of which are misunderstood. When you say that, as an overclocker, you don't need to worry about droop with Haswell, that doesn't mean the problem actually went away. It's still there, behind the scenes.
What I am getting at is that this adaptive voltage thing seems to be yet another
one of those ill-advised and poorly understood sliders. Why are you using it, again?
I mean, you've explicitly said that this strange behavior only occurs when it is on, but inexplicably you blame the CPU (and even stranger, the instruction extension AVX) and not the motherboard manufacturer. If you don't have it turned on, your CPU apparently doesn't get goosed with extra voltage.
It's still completely anecdotal, just like a forum. That guy didn't do a test, or even a thought experiment about how his proposed mechanism of action could even work.
And, again, if this behavior disappears when that "adaptive voltage" setting is disabled... yeah...
My evidence is though building and overclocking half a dozen haswell builds, they all do this sorry I don't have a whitepaper, deal with it or ignore it, no reason to be a sarcastic ass.
But, see, you aren't just positing an observation. You are positing causation.
I'm not disputing that you are seeing this, I am disputing that it makes any
kind of sense from Intel's perspective. Because, you know, it doesn't.
However, BIOS settings that do strange and inappropriate things and the ignorant overclockers who swear by them, well, that's unfortunately nothing new.
Anyone here with a haswell K chip can confirm if they want to back me up on this, just set to stock speed, set voltage to adaptive and +.001, open OCCT linpack with no AVX and you will see 1.2v, fire off prime and you will see 1.3v. *note, you will see the voltage jump .1 when you see prime using AVX, see my pictures below, the non-beta prime will not be running avx code, but it switches around, give it some time and you will see AVX in the results line (like in my pictures) and the voltage will jump.
First off, the better test would be Prime95 version 26 versus version 27. Apples-to-Apples, as much as we can.
Second off, we're already muddled because what you are really looking at is the VID, which can be different for each individual core in Haswell but yet your tools only report one number.
Third off, if this doesn't happen without
adaptive voltage enabled...
Fourth off, are you using blend? Don't do that. You want the smallest size FFT available, but your screenshots indicate sizes of 448K and 1024k That's too big. You're out of the L2 cache at that point. Only use the CPU torture test, which should give you 8-12K FFTs, that will guarantee maximal CPU usage.
I mean, I can understand why motherboard manufacturers might think that goosing the VIDs under heavy load might make sense, I'm just not sure why you think Intel has anything to do with it.