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get more vcore under load: vdroop pencil mod for p5b-deluxe (pics)

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graysky

Member
Joined
May 6, 2007
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.

combork9.jpg

vdroopzoomuc5.jpg

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!
 

Hazaro

Member
Joined
Apr 25, 2007
Wow, as soon as I saw the title I was already hesitant, but that looks really easy!

I might actually do this one.

My droop is 1.336V to 1.288V, 0.048V like you. I have a P5B vanilla.
 

Hazaro

Member
Joined
Apr 25, 2007
I was at Ralph's and they didn't have 2B pencil's hopefully campus store will have some.
 
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graysky

Member
Joined
May 6, 2007
Hazaro said:
Wow, as soon as I saw the title I was already hesitant, but that looks really easy!

It is easy dude. Took me longer to open the case and get under the desk than it did to actually "do" the mod. You'll be amazed w/ the result and your decrease in idle temps.

Hazaro said:
I was at Ralph's and they didn't have 2B pencil's hopefully campus store will have some.

Dunno what Ralph's is.. do you have a Staple's or Office Max chain of stores? You can usually find these pencils in the drafting section either as a stand-alone product, or in a pack. For example, mine came in a 4-pack called, "Design Drawing Pencil Set with Free Eraser." This one came with 4 pencils: 2B, HB, 2H, and JL whatever the hell that is. Again, don't waste your time looking through the thousands of pencils in the standard pencil section like I did. Ask an employee where they keep their drafting stuff and head there to look first.
 
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graysky

Member
Joined
May 6, 2007
I'm sure you'll both be happy w/ the result. Do go to the extra effort to find the correct pencil though.
 

Hazaro

Member
Joined
Apr 25, 2007
So I dropped by an art store and got a 2B and 6B pencil.

The 6B is a GENERAL'S CHARCOAL 557-6B ex. soft

It says charcoal, so I'm not sure if it's actually made of charcoal... or it's the color. Just double checking before I do anything to my mobo :)
 
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graysky

Member
Joined
May 6, 2007
@Hazaro: yeah the 6B is softer than the 2B look here and it also contains a slightly higher percentage of graphite. I can't speak to using it personally, but the 2B worked great for my P5B-Deluxe. If you're worried about it, just use the tested 2B.

To your second question about this mod working on the vanilla P5B. I have read about people doing it with success on this board although my only first hand experience is on my -Del version. Again, compare the pic I posted to your board layout, count the surface components and if they look just like the my pic, you're probably good to go.

Please report your results (before/after load and idle voltages) in the thread.
 

bing

Low Profile Senior
Joined
Jul 13, 2006
Location
Indonesia
Beware hazaro, looks like your P5B layout on that PWM controller (ADP3198) is different from P5B-Deluxe. Although both mobos using the same chip. Don't rush or I'm afraid that mod will toast the mobo if you do it at wrong component.

I suggest you do research more detail before doing that, or easier try search at other popular OC forums for some proven mod on that particular mobo model.
 
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graysky

Member
Joined
May 6, 2007
Yeah dude, your picture seems different from mine... just compare the way they're laid out using the screws as a reference. Can you post a larger zoomed out pic?
 

downer

Member
Joined
Apr 9, 2006
Location
PA
I have a question regarding the best type of pencil to use for pencil modding. I'm working on the memory mod for my 7900gs, and I just bought a pack of 8B pencils as I read those were best. I shaded the correct resistor on the card with the 8B pencil and measured the ohms with my volt meter. The ohms would not drop, I used acetone to clean the area and made another attempt with the same results. I then used a 2HB pencil that I had used previously and the ohms were quickly reduced. Does anyone have any idea as to why the 8B pencil failed to lessen the resistance across the resistor?

Sorry that this is a little off topic.
 
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graysky

Member
Joined
May 6, 2007
@downer - it's not that far off topic.

Have a look at the chart and table in this wikipedia article. an 8H is softer than a 2HB and as such contains more graphite. I can't explain your result unless you didn't apply enough material. In my experience, the 2B does a stellar job.
 

downer

Member
Joined
Apr 9, 2006
Location
PA
I applied a very liberal amount of graphite from the 8B pencil, after I wasn't seeing a reduction in ohms across the resistor, and still was unable to drop the resistance. With the 2HB I barely applied any and was close to my target of 544 ohms from the default of 608ohms. I'll most likely try the 8B pencil again at some point, but for now the 2HB is working out. I just find my results confusing. I'm not doubting that the 2B through 8B are better for volt modding, I just wasn't able to get the desired results from the 8B.