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Heya,
Just wanted to drop the question if anyone knows what the purpose behoind vdroop is. From what I understand, vroop is not just a design flaw. It is actually supposed to happen according to Intel spec papers.
So if it is like this by design, then what purpose does it have? Features are usually made for a purpose.
-Stigma
Good point, what is the point of reducing voltage when the cpu needs it most?
Yeah. vDroop is bad for overclockers. If the CPU's voltage drops below a stable point, especially under load, it's gonna crash. At stock it's fine, it probably is there to lower load temps.
With my current motherboard (P5B) we have the ADP3198 chip for regulating the cpu Vcore. If we take a look at the datasheet, on page 30 we see Vdroop mentioned. Maybe the chip designers recommend a certain feedback configuration and the mainbord designers just follow those recommendations without knowing that there is a better solution for this. Or maybe there is another reason, I'm no professional :)
Vdroop is there to lower the voltage to reduce power input into the chip to 'acceptable levels' under load as per Intels design specsheets. So when a MB manufacturer gets the specs for a new chip they are obliged to follow intels instructions.
I'm sure it also serves the pupose of prolonging the life of power MOSFETS on MB's too. But I think Stigma you may be asking the question... 'If the chips design voltage is within a certain voltage-current configuration, why don;t they just have no vdroop and just that lower V to start off with?' that i don't know!
That's a very good question.
I posted the answer to the OPs question almost two years ago yet my post went almost completely unnoticed. I believe I also linked to a PDF on Intel's webpage regarding voltage droop. It may still be searchable, depending on how far back the posts are archived.
The PDF might also explain why the original voltage isn't simply lowered without droop, but I don't remember anymore.
Darn, I don't get it.
Intel supposingly instruct the mobo manufacturer to implement i certain droop in the vcore under load?
Always belived this was manufactory shortcut to save $$..
Regards,
r.-
I allways thought that vdroop was just the permitted droop under load and that ideally there should be no droop.
But thats obviously not how many boards are designed.
So im not sure either....
Intel's data sheets for all of their processors specifically mention the voltage drop with load. It's on pages 20-21 on the data sheet for the Core 2 Duos for example:
http://download.intel.com/design/pro...s/31327802.pdf
From what I know on the subject, Intel designed their processors to still fully and reliably function with droop. This was to allow motherboard makers to use less expensive parts and less time doing R&D developing a circuit that features no droop (supposedly fairly difficult if you want it to last?).
As for why Intel requires droop to be implemented in a board? Got me....I do know the XBX does feature a reduced-droop setting in BIOS, so Intel does know it's not ideal for OCing.....
Quote:
Originally Posted by SoddemFX
QFT
Also, a rhetorical question:
Which is harder to compensate for, vdroop or vcore ripple?
It is a cost-cutting technology. As one VRM maker puts it, the droop "helps maintain output voltage regulation through load transients with fewer (or less costly) output capacitors."
Along with many of the points already mentioned, it's also a matter of a sizing question of the power regulation.
Building a vreg circuit with no droop when going from less than 10Amps at idle to instantly more than 100Amps at load requires a lot of components and more expensive parts.
This is particulary true for video cards.
Really, the only question is why can't they just lower the Vcore under non-load, too?
Why don't they just lower the default voltage?
Safety margins I guessQuote:
Originally Posted by wwwww
But for what?Quote:
Originally Posted by wittekakker
From what we overclockers know, the busy CPU needs the higher volts for stability and the idle CPU doesn't.
Why does Intel think that they cannot lower the volts on the idle CPU to the same level that they lower the Volts to when budy?
It's the exact opposite of what we know.
I was not responding on that. The message I replied to was about default voltage and why Intel puts it on X volt, or atleast that's what I think he ment.
A regulator's output voltage will decrease proportional to load (current). This is a great concept will dealing with multiple power supplies/generators as it allows for load sharing (beyong the scope of this topic). This is, however, NOT ideal when dealing with a single power supply and a single load (CPU). The job of a voltage regulator is to keep voltage as close to constant as possible over ALL ranges of current output. If CPU load where to increase drawing more amperage and the supply voltage were to decrease the situation would be one in which the power level (P=VI) would remain close to unchanged. Others have already hit the truth on the head though....in the end it comes down to two things, PCB real estate and $$$. ;)
-FCG
It doesn't explain why you have to start out with higher voltage, though.Quote:
Originally Posted by SoddemFX
First, sorry for kicking this thread to live again..but this issue has been bugging me for some weeks now :DQuote:
Originally Posted by crotale
Just did a droopmod on a P5WDH, it involved lowering the resistance on a single resistor from 50K to about 20K. Why could'nt, ASUS in this case, just use at 20K resistor in the first place?
This suggests to me that this is not a cost-issue at all..
btw, droopmod did help my stable OC.
think about what happens when processor exits from high load
the exact opposite of droop
Because statistically speaking ASUS would have a few more RMA's to deal with. Burned power regs anyone. :DQuote:
Originally Posted by roger_h99.nor
hey, how much was the stable OC affected by?
Should be plenty of explanation right here: http://www.thetechrepository.com/showthread.php?t=126
If you haven't already read it :D
This is my conclusion also.Quote:
Originally Posted by [XC] riptide
Orthosstable oc went from ~ 3,8 to ~ 4,0. A litle disapointing compared to the gain achived on my late S478/Prescott system.
Thx for link RyderOCZ . haven't seen that one before! Nice reading.
Holy smokes.Quote:
Originally Posted by RyderOCZ
I think I got even more confused then I was before.
Is there an explanation in English? ( unfortunately I dont speak Rocketscientish :( )
I know there are people here who do, so could you (please kindly) translate?
VDroop is inevitable, right? Is there any way to control it without VMods? http://bestsmileys.com/clueless/1.gif
How come the manufacturers dont make MBoards that would have less VDroop if it's possible with VMods? I don't mean tweaking the heck out of it - just control VDroop better? They have all the means for this to be done safely... Improved performance would sell more motherboards and bring more recognition by experient users. Am I wrong?
Simply put vdroop is necessary to stop you trashing your cpu in the long run. Think of it like this, using simple science :)Quote:
Originally Posted by Geek77
Power = Voltage x Current
We wanna run our cpu at a set voltage so now:
Power is proportional to current
Logically your cpu uses nore power when loaded than when idling along ie it needs more current
Because of the limitations of the power circuit (and life) you cannot instantaniously supply a large current (it needs time to build up) therefore if you suddenly have to supply a large current then the voltage will momentarily sag (like if you changed up a gear on your car).
The opposite happend when the load is removed, the voltage will "overshoot" monentarily until settling back down. Now as Kris has pointed out that the purpose of vdroop is to counteract this overshoot (amongst otherthings) so instead of suddenly going up from 1.55 to say 1.85volts it'll be more like 1.55 to 1.65volts. Obviously if you subject your cpu to a constant barrage of 1.85volt spikes it won't thank you for it.
The amount of vdroop however does depend on how the board designer desides to impliment Intels guidelines on the matter, and some people feel it is a tad excessive on some boards. Also don't confuse vdroop with "vdrop" a term coined for the difference between the voltage you set in the bios and the actual voltage at idle
ya wanna know what vdroop is...its Intels way of puttin out crap gear and then having to make adjustments to compensate....INTEL cares about ONE thing $$$$$$$$$$$...they do not care about you, your' over clocking, or their customers. They have such a large market share....they don't need to care. Further they have not had one original thought since before the 286...they continually reverse engineer other companies products......steal their ideas, and due to their excess of money...convince consumers that they make better equipment and that they orginally designed it.
The only way to make INTEL start listening to YOU...is to stop buying their products...THEN they will hear you :/
Um...did you even read the thread?Quote:
Originally Posted by ghot
You do realize that it's not a design flaw within a processor, it's on the board right? They design a board to run their processors, because those are the boards the Intel sells. No more, no less. They generally let Asus/Gigabyte/DFI/MSI/etc take on the overclocking crowd, so how is it Intel's fault that these other boards are designed the way they are?
And like was said previously, it's a good thing to have for the average person.
the problem for me with all of this is you dont see AMD system drooping like this.. so,, why has intel adopted such a thing.
the only amd systems that i saw droop as bad as intel were very cheap motherboards with poopy components.
aside from heat regulation ie; increased cpu cycles increases heat so lower the voltages to counter or help offset the heat.
i see no true reason for it.
look at your other components around your house. atleast from my tests with a kill-a-watt device there isnt any droop.
but i also am not testing internally i am testing at the source so it may indeed dropp internally but i doubt it.
Could it have something to do with heat... you know, for stock systems? letting voltage sag under none load would reduce heat? Maybe they did it to make there units run with less power consumption too. It is kinda strange that chip designers make these specs and just pass it on for the mobo makers to follow... But i guess it could be worse, we could all have intel mobo's to run intel cpus... eww...
Edit: maybe thats what voltage stepping is for thou... grr... maybe it works with voltage stepping?!
actually i don't know anyboard without vdrop, so it's intel and Amd's spec's too
There is boards that have almost zero drop=)
And you have mobos thats drops like a bomb under load:(