get more vcore under load: vdroop pencil mod (pics)

[graysky]

This is one of the easiest mods you can do to your P5B-Deluxe (and probably any P5B although I haven't tested it on any model but the Deluxe) to help you get higher voltages under load conditions and also lower your idle vcore; it is particularly useful for people wanting to get more juice to feed their o/c'ed chip.

Background
As you know, the P5B-Deluxe (and others in the P5B family) has a vdroop built in for some reason (protect processor maybe, I dunno). Vdroop is the term used to describe the voltage drop between idle and load conditions.

Try it yourself right now: (assuming you have your vcore manually set in your BIOS) load up CPU-Z and see what it's reporting as your idle vcore. Now load up a few instances of orthos and have a look. For example, before the mod, mine dropped from 1.280v (idle) to 1.232v (load) which is -0.048v! After you do the "pencil mod" it should drop by a very small amount or none.

The "Pencil" Mod

What do you need? A soft pencil. Look for one with a 2B rating on it. Standard pencils are HB. HB pencils will work, but the softer the pencil lead, the better the results. You can find a 2B pencil at most any office supply store (staples, officemax, etc.); they are usually in the art or drafting section (aisle #7 for my staples). I got one in 4 pack for under $3.

Now, either unplug or switch off your power supply so the LED has gone out and simply shade (gently draw with the pencil back and forth) over the correct surface mount component (it's a resistor maybe?) -- refer to the pictures below... it's the one with the yellow arrow pointing to it.

zoomed out pic
zoomed in pic
You can see on the zoom where I colored over the right one.

NOW, boot into Windows and repeat that exercise where you measure the load and idle vcore. Mine went from a drop of 0.048v before I did the mod to a drop of 0.008v after the mod. These are both @ a BIOS vcore of 1.3250v.

I recently lowered the BIOS vcore to 1.2625v and now I have NO vdroop at all: idle is 1.232v and load is 1.232v, and the system is stable to 2x orthos for over 6 h!

Undoing the "Pencil" Mod

You can undo this very easily with a little alcohol and a few q-tips. It is 100 % reversible.

If you found this useful, please post your before/after results in this thread.

Enjoy!

[Shimmishim]

pencil mods are nice... but i prefer to hardmod mine.

i've heard of people killing their mobo due to stray graphite... i recommend anyone that pencil droop mods or vcore mods be VERY VERY VERY careful.

[soydios]

Is there any way to fix vDroop on a P5W?

[Shimmishim]

Originally posted by: soydios
Is there any way to fix vDroop on a P5W?

yes.

the vdroop mod for the p5w i believe is the same as the p5b deluxe as well

[gramboh]

I'm thinking about trying this on my P5B-D (I have about 0.05v Vdroop) so that I can lower my Vcore a bit. I'm a bit worried about stray graphite (conductive) screwing something up since I don't have the most steady hands.

Then again I bought instant product replacement warranty from my retailer so I could get them to give me a new board over the counter if I ruin it.

[graysky]

@gramboh -- I think boards are more robust than that. Just give the board a hit w/ some compressed air if you're worried.

[SinfulWeeper]

Anyone try this on a Commando?

[graysky]

Try googling commando pencil or commando vdroop mod etc. The forums are full of posts from people who pencil modded their commandos. I just can't find a how-to guide for you.

[MetaDFF]

Just a FYI for the Asus P5K Deluxe motherboard owners.
If you have a Asus P5K Deluxe motherboard it isn't necessary to do a pencil mod to fix the Vdroop.
In the BIOS there is an option called CPU Voltage Damper that you can ENABLE to minimize the Vdroop. (In my case it drops about 0.01 V).

There is actually more info specific to P5K overclocking that can be found here:
P5K Overclocking (HEXUS)

Edit: It looks like the CPU Voltage Damper droops less when you are setting the core voltage via AUTO. It seems like the P5K likes to overvolt the chip when overclocking with voltages set to AUTO.

[CTho9305]

Doing this seems like a really bad idea to me. Vdroop is used to cut costs - basically, they can use less capacitance on the output of the voltage regulator and still supply "good enough" power to the CPU by simply overvolting it slightly when it's not drawing much current, and undervolting slightly when it's drawing a lot of current.

The naive reaction would be, "well, I'll disable this and always supply the right voltage". A user does that, and verifies with some voltage measuring tools (a multimeter, software, whatever) that the voltages look better. But the user missed what really changed. With active voltage positioning enabled, the transient spikes in the power supply are reduced but the steady-state voltages look worse. With it disabled, the steady-state voltages look better, but transient spikes will be worse (and AFAIK there is no way for software to detect the transients). If the CPU suddenly transitions from idle to load, there will be a brief moment when it is significantly undervolted (and, like any undervolted CPU, may crash / corrupt your data / whatever).

Mark R found this very informative article that explains active voltage positioning / vdroop.

[killnine]

I have a rev. 1.02G P5W-DH and NO ONE has any info on performing this pencil mod on it. THe layout is different and it pisses me off that no one can offer an inkling of help about it.

Doesn't anyone without a 1.0G pencil mod their board?

[kmmatney]

I wouldn't worry about this, but you can blow some air and put a small piece of tape over the pencil marks just in case.