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Facepalm
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There's been a lot of talk from people over what the absolute maximum voltage for Sandy Bridge cpu's are, and the "safe maximum."

Note: if you don't like reading: please skip to the next thread (tl;dr). But if you want some more information about this "VID" stuff, read on.

The VID range, is a range of voltages, between minimum and maximum VID range, which the CPU's can be calibrated to request as an automatic voltage (when the CPU vcore is set to "automatic", and which can be read from a register inside the CPU, based on its operating parameters).

That's NOT the same as maximum safe voltage.
The tech documents actually explain this.

This is from tech document 1 of 2 (January 2011):
Quote:
The processor uses three signals for the serial voltage identification interface to support
automatic selection of voltages. Table 7-1 specifies the voltage level corresponding to
the eight bit VID value transmitted over serial VID. A '1' in this table refers to a high
voltage level and a '0' refers to a low voltage level. If the voltage regulation circuit
cannot supply the voltage that is requested, the voltage regulator must disable itself.
VID signals are CMOS push/pull drivers. Refer to Table 7-9 for the DC specifications for
these signals. The VID codes will change due to temperature and/or current load
changes in order to minimize the power of the part. A voltage range is provided in
Table 7-5. The specifications are set so that one voltage regulator can operate with all
supported frequencies.
Individual processor VID values may be set during manufacturing so that two devices
at the same core frequency may have different default VID settings
. This is shown in
the VID range values in Table 7-5. The processor provides the ability to operate while
transitioning to an adjacent VID and its associated voltage. This will represent a DC
shift in the loadline.
The VID is set for EACH individual CPU, and it's set that TWO IDENTICAL CPU's might have different VID levels!

Now it would take an intel engineer to come in here and explain why one CPU has a default VID at 3.4 ghz, of 1.212v, while another CPU has a default VID at 3.4 ghz at 1.250v. However, at least from pretty standard testing over the last few years, CPU's with lower VIDS tend to overclock farther than CPU's with higher VIDS. However, it was also determined over on xtremesystems, that CPU's with lower vids, that overclocked better, sometimes ran hotter (aka "leaky chip").

Also, it's clear from the way the VID chart progresses from 3.4 ghz to 3.8 ghz, that Intel directly tests the cpu's at these fully supported speeds (Turbo boost is 100% guaranteed by Intel). And the vid skyrockets between 3.4 to 4 ghz. But then the default VID for each multplier seems to bottom out (I suspect that the chips are not tested at higher multis, but the VID is made so that the chip will at least be able to complete POST; someone with knowledge of VRD 12 can hopefully fill in more information).

Intel tests their cpu's to see how they perform at harsh operations (which is one reason why Linpack exists), and I suspect their CPU's are either binned according to several specific torture tests, or have the VID signal implanted into the CPU based on how well it does on these tests.

The 1.52v that you see on the charts is the absolute MAXIMUM VID that is allowable under the VRD 12 specification, and if you look at the binary field charts, you can find that out from the binary on/off bits. It does NOT mean that the particular CPU sample can handle that VID or even has it implanted in its voltage request table at high frequencies. In fact, there is probably NO cpu even made that has a default VID as high as 1.52v at a x58 multiplier, for example.

Now what's interesting is, older CPU's used a VID range from 0.825v-1.3625v or 1.4v, but the binary VID chart goes up to 1.6v on those. But only goes up to 1.52v here.

ANOTHER problem is that on the previous cpu's, intel specified an absolute maximum voltage, beyond which (at least on air cooling) that the cpu's WOULD start taking damage, and this absolute maximum was HIGHER than the "Vid range" shown in the number figure, but always LOWER than the "Vid chart" shown on the binary bit chart.

Needless to say, this isn't exactly user friendly.
What's even worse, the specification update is for ERRATA.

Someone really needs to contact Intel and have them explain "what happened to the absolute minimum and maximum ratings" section.

In summary, NO ONE Knows the "absolute minimum and maximum ratings" for the voltage, because Intel has NOT specified them. Also, NO ONE knows why Intel is using the "Vid range" from the binary vid chart (0.25v-1.52v) for these processors, when the previous cpu's had different results for the binary vid chart (-0.3v (I think; I remember it was negative voltage) to 1.60v), and the vid range (0.825v-1.3625 (or 1.4v). with an "absolute maximum" in yet another table that was always higher than the "VID range". But I have no idea why the binary VID chart had this range, when the VID range was much smaller.

Until someone can explain if the VID range was increased deliberately for VRD 12, and the CPU's made more tolerant to vcore, or if Intel made an error, by just copying the binary VID chart (very, very likely), that will have to wait until someone can find out the truth.
 

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Dream Chaser
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So what you are saying is.....after 88 MPH, I have to get MORE plutonium.
 
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Hummmm....
headscratch.gif
 

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Dream Chaser
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Quote:
Originally Posted by nagle3092;12942503
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That made my night, thanks.
One does what one can. It is skeptical though what intel is doing with these chips. I agree on the lack of support here. But hell, these chips are OC'ing faster than people jumping out of chairs at the Michael J Fox barbershop. Besides, I have phase. That'll be my new mantra....

"You can't OC with that voltage, thats madness...."

"Relax bro, I have phase." lol
 

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Facepalm
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Discussion Starter #11
You guys crack me up...
 

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The topic starter is typed this big story, to inform you guys.

And all you do is make fun of him with your comments......
 

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Dream Chaser
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Quote:
Originally Posted by prescotter;12944403
The topic starter is typed this big story, to inform you guys.

And all you do is make fun of him with your comments......
Ummm no, we are not making fun of him. Its geared more toward Intel being vague about their SB chips.
 

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Any updates to this, or should we still stay at 1.385v till then ?
 

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Facepalm
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Discussion Starter #16
Was there any real need to necro this?

And the maximum safe voltage IS* 1.38-1.39v.
I have proof now.

What's the maximum VID?

1.52v.
Now, set that in your BIOS, with a reasonable overclock (at least 4.5 ghz at the minimum), do NOT use loadline calibration, and then run Prime 95 small FFT's (not blend) or Linpack with AVX extensions (requires SP1), and then tell me what the vcore reads....

(Hint: The max VID assumes you are NOT using loadline calibration, which goes out of official specs).

I'm not taking credit for that--it was some other poster yesterday who mentioned this....but I can't find where it was...it was in one of the 2600k threads....
 
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Quote:
Originally Posted by Falkentyne;13592452
Was there any real need to necro this?

And the maximum safe voltage IS* 1.38-1.39v.
I have proof now.

What's the maximum VID?

1.52v.
Now, set that in your BIOS, with a reasonable overclock (at least 4.5 ghz at the minimum), do NOT use loadline calibration, and then run Prime 95 small FFT's (not blend) or Linpack with AVX extensions (requires SP1), and then tell me what the vcore reads....

(Hint: The max VID assumes you are NOT using loadline calibration, which goes out of official specs).

I'm not taking credit for that--it was some other poster yesterday who mentioned this....but I can't find where it was...it was in one of the 2600k threads....
I guess its better to just start a new thread and ask the same question instead of just reviving an old thread for updated information, sorry I was such a bother and have offended you by upping your thread. I'll keep that in mind next time.

I've set my bios voltage to 1.5200v w/o LLC I get 1.500v idle and 1.404v loaded in both CPU-Z and DMM.

Thanks for the confirmation, that info was not really readily available anywhere to me.
 
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As far as I know, it has nothing to do with voltage levels, but rather the byproduct of increased voltage, aka heat. Come on guys, this is basic physics 101. The only real VID range that would exist in the SB CPU's, particularly the unlocked "K" series chips, would be a min/max voltage limit that would be designed into the chip. If this is the case, then their K series processors were not technically "unlocked, so they falsely advertised that.

Like I said before, people think that too much voltage will cause some sort of failure purely because of the voltage, which is simply not true. Thus, these processors should have no problems running at any voltage level, granted they are able to keep temps within hardware-safe levels. So I'm confused why there is so much attention placed on voltage, rather than temp. Two Core i7 2600k processors in the same rig setups are nevertheless going to produce different temps at the same voltage levels, so I don't see how it would be feasible to gauge CPU capabilities based specifically and solely on voltage levels....
 

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Facepalm
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Discussion Starter #20
Quote:
Originally Posted by EarlZ;13592799
I guess its better to just start a new thread and ask the same question instead of just reviving an old thread for updated information, sorry I was such a bother and have offended you by upping your thread. I'll keep that in mind next time.

I've set my bios voltage to 1.5200v w/o LLC I get 1.500v idle and 1.404v loaded in both CPU-Z and DMM.

Thanks for the confirmation, that info was not really readily available anywhere to me.
You didn't offend me. It's just better to start a new thread when topics are that old. Now if a forum is pretty inactive (e.g. a few posts each week), then that's different. Besides, I was clearly wrong in my original post anyway, and now it just makes me feel more wrong since i tried to sound like a genius in the OP, which clearly I am not. Since there I never took into account that LLC was NEVER intended to be used "officially", so 1.52v w/o LLC becomes around 1.4v'ish.

The person who is the real genius is the one who mentioned that Max VID Was supposed to be used with LLC to get the real voltage....

On mine, its 1.392v if I set 1.52v in BIOS at full load (which, since the vcore is read in 0.012v increments with the sensors, could be anywhere between 1.385v-1.398v of real vcore). It's 1.476v at idle. That's a MASSIVE vdroop, though....0.080v droop just from idle to load...
 
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