alot of people says the issue with certain asus board.. in particular the VDroop prevents successfull overclocking.. is that so?

and according to asus website..



Source : http://support.asus.com/faq/faq.aspx?no=BB...SLanguage=en-us

can some1 clarify?

i think almost all of intel board experience tis Vdrop, it is absolutely normal
u can mod the board to prevent any Vdrop

Its a drop of CPU voltage when the CPU is taking a lot of power. Happens when the voltage regulator on the motherboard is not well designed. Usually for socket 775 processors a 4 phase or better power regulator is recommended.

For boards suffering from vdroop, sometimes overclockers voltmod them for higher voltage to compensate for the voltage drop. Setting a higher voltage in bios is also possible, but often results are unsatisfactory. But increasing the voltage has its problems as well, as when the processor is idle, the voltage will be quite high (no voltage drop), which may damage the processor.

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Added on June 24, 2007, 4:17 pmAnd yes, it also affects other boards, not just Asus. Asus is often mentioned because they used to often use really small mosfets in the voltage regulator which were prone to overheating (which causes mosfets to conduct less current)

yeah... it's normal... tat's y ppl want more powerful PSU ma... if nt Enermax, Tagan and other lords of PSU will eat grass to survive lo...

i don't think its becoz of PSU.. its got to do with the voltage regulators on the motherboard

even a powerful PSU cannot prevent the Vdrop

another myth...

Vdroop is a design, read through this article if youre interested:Vdroop

Most Asus board (C2D) have terrible vdroop, even for asus commando iirc, when cpu is loaded, Vcore will drop because the power circuit design, thus lowering the Vcore than specified in bios, hence, cpu not getting enough juice and restarts. So there be pencil mods for vdroop, for extreme overclockers.

HTH

Not a chance. Even with a PSU with adjustable rails there will still be vdroop if the mobo voltage regulator is not well designed.




Cool article. Downside of pencil mods and other hard mods is they don't solve the vdroop problem entirely or introduce problems of their own. But anyway only very hardcore overclockers will care...

HAH!!! Of all the makers to publish something concerning VDroop, it had to be Asus. Brrrrrrr........You should measure the VDroop with a DMM for the P5B series, it'll give you the shivers

And seriously, what is written in that article is rubbishing. If you really want to know about VDroop, read this instead: http://www.thetechrepository.com/showthread.php?t=126

No doubt it's more technical but it explains the real truth

^^

ok.. i've browse through the tech repository.. and i dun understand it.

so this vdroop is part of the design spec? and not a dreaded problem?

This one,i think is something related to P=VI where your P is at a certain valur while your V is dropping,I will increase the value to compensate the loss of V. THus the compensation make the mosfet area become hotter.

It IS a problem, and has to be taken into account during design, as its pretty much unavoidable. Although its important to minimise it, its not cost effective to use a very complex design, so manufacturers make do with simpler, cheaper designs that work and compensate by adjusting the voltage to a value where vdroop is still acceptable. The problem starts during overclocking, as higher power consumption in overclocking will mean more current, which will cause the vdroop to be more severe. There will be minimal vdroop when the processor is at idle, but severe vdroop when the processor is fully loaded, which is bad, as overclockers may increase voltage to high levels to compensate for vdroop, and the absence of vdroop in idle will mean the voltage may be dangerously high (processor damage possible).



You better double check that, the formula should be V=IR, where V is the resulting voltage drop, I is the current taken by the processor, and R is the equivalent series resistance in the voltage regulator circuit from the sensing point to the processor.

P=VI is to calculate power usage, specifically conversion from electricity to heat (which applies in almost all electrical devices). Although your description does explain a downside of vdroop, it does not explain accurately why it happens. Yes, a poorly designed board suffering severe vdroop will actually make the problem of overheating MOSFETs worse and worse, as the voltage drop (using V=IR) across overheated MOSFETs will result in a power loss and they will overheat more. And the more the MOSFETs are overheated the worse the voltage drop-a vicious cycle. Contrary to your explaination, current (I) can only be increase up to a certain point until the MOSFETs are working at full capacity-which would be limited by overheating (a safety feature of MOSFETs).

interesting explanation... so how do we know the MOSFETs are working at full capacity...?

Vdroop happens when CPU draw current from the CPU Voltage regulator. At certain times CPU can draw as much as 100A. So Vdroop is unavoidable. There is a vdroop spec and most board designers will design so the droop will not violate the Vdroop specs.


For this Vdroop problem, there are a few ways to improve it and it requires you to rework (change components) the board. It will void your warrenty and so try it at you own risk.

1. Put higher capacitance caps or better quality capacitors around the cpu socket.
2. Fill in the empty capacitor slots around the CPU with simillar capacitors.
3. Do some compensation tuning to the cpu voltage regulator. You will need to know the voltage regulator very well and expert in control theory. Not recommended.

There's no sure way of finding out unless you are very familiar with the voltage regulator circuit of that particular motherboard. At best, you can guess the peak current of the mosfets during the max duty cycle of the voltage regulator by estimating from the power usage of the processor. If the number you come up with is higher than the rated current for the mosfets, then the mosfets are overloaded. However, finding out the exact current used by the processor is a major problem, even the best estimates can be off by quite a bit unless you have proper equipment and are prepared to hard-mod the motherboard.




Sucess rate of 1 & 2 highly depends on how well the voltage regulator circuit was designed in the first place. If the manufacturers decided to cut costs by using fewer or lower quality caps, then you'll improve on it. However, if the circuit was already well-designed to start with, you may just screw everything up, with potential problems like PSU damage (due to surge current at startup), voltage fluctuations (due to the different circuit harmonics),

3 (AKA hard-modding) on the other hand, has been done by overclockers with some success, but like you said, need to be very familiar with the circuit. I did it once before, seriously its not for the faint of heart.

What lohwenli said is true, you will need to hardmod the board to put a current probe the measure the current exactly. I have seen people done before and its not an easy task. The end result is a messed up board after the measurement. But if you dont want to hardmod the board, a good indication if you mosfet is work hard is check the temperature. Usually the at ghigh current draw, the mosfet temperature will be around 70-90 celcius

Question on this Vdroop thingy....

Say that I set 1.45v vcore in BIOS. In windows, vcore is 1.41v and at load it drops down to 1.38v (using any app e.g. CPUz or speedfan)

If that is the case, if I compensate for the vdroop, would this put too much strain on the proc? e.g. 1.50v in BIOS, 1.45v idle in windows, and vdroop 1.41v.

I mean, if the CPU is running at 1.41v at load due to vdroop, then theorectically the CPU is only receiving that much amount of voltage rather than the vcore at idle, right? (which is 1.45v in windows or maybe correctly at 1.50v as set in BIOS)

Anybody can clarify this?

Note : I realize that software monitoring is inaccurate but for the drop in voltage, I guess that would be quite accurate right?

there is nuthin' to do with psu..
its the board design itself & the worst still, asus board vdroop amongst all board maker

I hafta gree with that...i have tried a number of ASUS boards from 965p to 975...both have serious vdroop at high OC

So far, the P35 is the best....very very low vdroop or can consider as no vdroop at all.

its aint the p35 chipset, it the manufacturer fault i believe as badaxe2 also using 975p but very2 little vdr0op

mmm...some clarification required...i tot i understand about vdroop but...
taking example given by kmarc:
V(bios) = 1.45v
V(idle) = 1.41v
V(load) = 1.38v

so, which one is considered as vdroop? when the proc at load or between bios setting and V(idle) or between all?

Dun use MB probe to check....it's best you use a DMM to measure. You take the readings on load and idle. Minus them you will get the vdroop value.

haha...for those who don have the DMM, then the apps will be the only choice la...
anyway...i just wanna have some clarification (either via apps or DMM), the vdroop is measured between the idle and load, isnt it?
but what about the different between bios setup and windows loaded reading...will that be considered as vdroop as well or not.
just to get things clear about this thing...thanks

Like you said...no DMM, then just use the apps. But it's sometimes inaccurate. Some mobo undervolts and some mobo overvolts. And sometimes the apps give inaccurate reading too. So it's always advisable to use a DMM to meassure especially if you wanna do a vdroop mod.

if u gotta DMM, then its better to measure the voltage. both bold value consider as vdroop

it should be stable in any situation no matter idle or load..

Thanx for the clarification. Another question , some people suggested that to reduce the vdroop, you have to increase the vFSB. Is this a myth or truth? (Bring out the mystbusters!!!)

not quite sure as ive try upon my board(asus), still the vdroop margin kinda high

ex, my current BIOS voltage for cpu was 1.400v but when i restart my pc & go into voltage monitoring(in BIOS environment) its fluctuate between 1.344v ~ 1.36v even increase the RAM, SB, SB Pci-e & NB voltages, its still da same

Yeah, my vdroop was still the same even though I've increased the vFSB. I though it was because of my DS3 (the cheaper good performance mobo!).....

i c...in windows, either at idle or load, the voltage seems to be very solid...
it just the setting in bios and windows voltage is different...
so, no problem during the load stage...just that i need to set a bit higher in bios to achieve the target voltage

Don't go too high on the vcore though..... and watch you load core temperature too.

How much higher are you thinking of going?

No, no...what i meant by higher is just to compensate the vdroop...e.g. if i want to set 1.4v...then during windows application or on load, i got 1.38v...then i just set the vcore to be 0.02v higher...to get roughly 1.4v...anyway, depending on cooling, on daily i will not go beyond 1.45v...normally i stick to sub 1.4v(drooped to 1.38v) for daily operation

Anyways to have a better technical understanding,
read HERE

haha guys u cannot change the boards vdrop and vdroop.

vdrop is the difference between bios set and idle real.

vdroop is the difference between idle real and load real.

the only way a board can change its vdrop is bios.

the only way for a board to have less vdroop is mod. u need to pencil mod or something to "overcome" that vdroop. so always remember to set mroe voltage for u get less.

also different fsb and cpu volt ahve different drops and droops. usually the higher u go for ur fsb and mhz, the higher your vcore, the more the droop and drop.

personally gigabyte dq6 series has the least vdroop (virtual 12 phrase)and asus boards like striker and blitz have the least vdrop - 8 phrase

haha.. same here lerr, i hafta put 1.400V to get 1.350V.. zZZZz ohH asus

Now setting to 1.485 volt in BIOS to stabilize my oc. In windows range from 1.46~1.48.

hahaha...
based on NightRaven explanation (thanks bro), i only have vdrop i.e. voltage is different/lower than what i set in the bios roughly 0.02v
vdroop...don have
idle or load, it stick to it...using OCCT, u can get the graph for the voltage as well as the temp...always got 0.00% ripple for vcore.
so, yes, DQ6 really has very minimal vdroop if not none at all. it rox

nice laa, mine got both vdrop & vdroop
in BIOS set 1.4V then i'll get 1.355v roughly
middle of prime, it woll decrease again at 1.32v/ 1.31v..

wow...the vdrop is so bad one...0.045v
so again: migrate!migrate!migrate!migrate to P35

haha p35 will be the same la bro! u need to see which board...

anyway thanks for the compliment bro

this vdroop problem affect stability issue or not? since >0.05v different consider much for todays cpu

sometimes its does makes the difference between stable at 1.45v and 1.4v u know

i'm on AMD.. since this most happens on intel user..
theorically.. it's should does affect the stability.. but just need to know from intel user's experince itself..
any obvious affect? lag or something?

lagging is more on the performance...this vdroop might effect the stability...running fine and all the sudden, something crashing here and there

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Added on August 15, 2007, 2:06 pm
yup, the same i.e. got the vdrop but not as much as the gengstapo one...heheh...
actually has been poisoning him to switch to p35 but he said retired...it's like retired people but went to the office everyday...seems funny la...

@geng, jk only

Thx for the explanation.

Regarding the vdrop, does all mobo have the vdrop? Will any mobo actually have a higher voltage?

For example, if we set 1.45v for vcore in BIOS, can we safely assume that the mobo will be running at a slightly lower vcore (due to the vdrop) and will NOT be running any higher than 1.45v.....



Le, mine is a P35-DS3 la, which I consider to be a cheap "performance" mobo (can get for rm400!).
Actual setting in BIOS for vcore : 1.425v

CPU-z at idle : 1.392v
CPUz at load : 1.360v

Easytuner5 at idle : 1.41v
Easytuner5 at load : 1.38v

So, unless you have an "expensive" high performance mobo, I guess you'll just have to live with it.....

hey guys. ALL mobos will ahve vdrop and droop. just how much only yes higher perf board usually have less droop so.. yea have to live with it

amd also will have

yea only effect is stability

@8tvt, since not much talking about AMD oc lately dunno if vdroop does have particular issue.

i look on cpu-z.. during load the voltage is same as set in the bios..
sometimes even higher on idle.. it's never below what i set in the bios..
the different also not much.. around 0.02v..
i never experince system prob..
but only sometimes when playing certain games lag for least then 1sec.. i suspected that's gpu related..

well, used to with AMD Athlon64 3000+ Venice E6, BIOS set at "Auto" with software reading (CPUz) at 1.376vCORE, when switched to AMD Athlon FX-60 Toledo, BIOS also set at "Auto" and on CPUz, it's 1.312vCORE , there is a dropping...



FX-60's details

mine funny case... set in bios 1.50 but while load the uguru detect 1.52... mine vdruuUP ah??? lol...