Backwards Vdroop, 780i

[cirro]

Okay, so originally my 780i i found out after I started to OC had an ENORMOUS vdroop (sometimes depending on the rising vcore) it would get up to nearly 0.06,

so i did the vdroop mod (pencil) , then had a little instability at first, then i re-did the pencilling(?) and it re-gained stability,

but anymore i notice that its coming back , i assum i addded to much,but now for some reason it can grab itself (at peak load only) +0.03 onto the Max Vcore i set in bios

 

can i just erase it and try it again? or will i usually get these results with a pencil mod?

[SMeeD]

The penciling could be wearing away a little bit. You can try a metallic pen which you can find at radio shack or any type of metallic paint. I went out and bought a repair kit for rear window defroster leads and used that for my ultra-D SLI mod and its been fine for a year or two.

[hardnrg]

do NOT use metallic paint or other conductive pens for a pencil mod!!

 

a pencil mod lowers the resistance of a resistor by making a parallel resistor network made up of the resistor and a layer of graphite laying on top... metallic conductive ink/paint would effectively making the resistance zero, and for a volt-mod, this will mean serious damage and disaster

 

erase the graphite off the resistor... start again... maybe use a different value pencil like I used a 4B instead of the suggested 2B so that the graphite is "thicker", and then I put a piece of clear tape over it...

 

I did the pencil mod while the system was running, and I used Prime95 v25, OCCT v2, and HyperPi whilst having CPU-Z open in order to determine the idle/load vDroop and eliminate it...

[SMeeD]

a pencil mod lowers the resistance of a resistor by making a parallel resistor network made up of the resistor and a layer of graphite laying on top... metallic conductive ink/paint would effectively making the resistance zero, and for a volt-mod, this will mean serious damage and disaster

 

Haha, oops that wouldnt turn out so hot. I guess I didnt realize how it worked

[The Smith]

I have another suggestion. Instead of

putting a piece of clear tape over it

, take your glue gun and put some on the resistor. It hangs better and it is also easy to pull off.

 

@Hardnrg: I did a vdroop on my P35-DS3R by soldering the two legs of the resistor. Two weeks after I un-modded it there was no damage. And I saw on many websites that conductive ink is a good idea. So you say that it would be better to solder another resistor in parallel ??

Edited June 28, 2008 by The Smith

[Branjo]

With a pencil the mod is completely reversible.

[hardnrg]

@Hardnrg: I did a vdroop on my P35-DS3R by soldering the two legs of the resistor. Two weeks after I un-modded it there was no damage. And I saw on many websites that conductive ink is a good idea. So you say that it would be better to solder another resistor in parallel ??

On the reference 680i/780i boards, the vDroop mod relies on lowering the resistance value of one of two resistors. This can be achieved fairly easily and with a decent amount of control using the application of graphite from a pencil.

 

Hard-modding the voltmod with a variable multi-turn resistor (18- or 24-turn) would be a more precise method that you could tweak easily by simply turning the resistor, but soldering to SMD components is quite difficult in comparison to simply drawing with a pencil

 

It's quite easy to desolder an SMD resistor when tacking on wires to each end, so I'd only recommend it if you are 100% confident with your soldering skills.

 

Just don't use a standard single turn variable resistor (potentiometer) as the precision is nowhere near suitable.