I7 920 D0 not stable at 4.2GHz

[RJR]

In the BIOS, you set the maximum voltage. Those ringbacks cannot exceed that voltage. Therefore, since there always will be ringbacks, Intel/AMD/Ted's Processor Manufacturing Emporium/whoever HAS to incorporate a voltage buffer on the chip, which is your Vdrop, or else the chip would overvolt every single time.

Not exactly true. The voltage set in the Bios has nothing to do with a maximum. Your voltage can spike/ringback beyond your Bios set voltage with LLC disabled. You can enable LLC and actually have an idle and or load voltage of more than what is set in the Bios. Even with LLC disabled, if your board has a very good PWM and lots of capacitors the spikes/ringbacks will be minimized and will allow you many more options to use LLC or not without the risk of very high spike/ringback values. Now, the kicker is the duration of said spikes/ringbacks, even Intel has a spec on this stating if it's duration is less than XX, you don't even have to worry about it. So far I've never found anyone that actually took a processor and a scope and sat down and mapped it all out, letting everyone know the length and duration of said spikes/ringbacks with different configurations. OK, now i'm just babbling on, here's an interesting article on vdroop: http://www.thetechrepository.com/showthread.php?t=126

 

OH, and yes the vdroop/vdrop is a spec of Intel's that most board manufacturers follow (not all) to give you a little insurance against very high spikes/ringbacks at stock vcore, but the spikes/ringbacks do increase as you increase the vcore.

[ebarone]

I shouldnt have said "cannot"... not only is it grammatically incorrect but you're right, its also misleading... Bottom line is, the BIOS voltage setting is not intended to be the target voltage. The target voltage is V(bios) minus Vdrop for idle, and V(bios) minus Vdrop minus Vdroop for load. At least, thats the way Intel intends. But you're right, the BIOS setting is not some hard ceiling that cant be crossed.I've never used LLC, but I've always been of the impression that its a product of board manufacturers in response to people doing pencil mods and whatnot to get rid of their drops and droops. I saw once an actual graph of the spikes vs time, I cant find it now though... it was very interesting to see.

 

At any rate... pump that voltage

[dling]

It looks like your memory voltage is low. Try setting it to 1.65 or 1.66v .