Originally Posted by born2bwild
You're right. they must have updated it from the last time I checked.. which was a while ago.
Unfortunately, that's NOT the maximum voltage.
That's the maximum VID, which the CPU's can be calibrated to request as an automatic voltage.
That's NOT the same as maximum safe voltage.
The tech documents actually explain this.
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.
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.
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 (0.2v-1.52v) for these processors, when the previous cpu's had different results for the binary vid chart (-0.3v 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".
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.Edited by Falkentyne - 3/30/11 at 10:48pm