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Role of capacitors in voltmod

post #1 of 8
Thread Starter 
hi guys i saw some pics here that people soldered caps on the graphic card pcb.. can some one please tell me in detail :-
1. what is the role of capcitors in voltmodding graphic card ?
2. how to detect the value of capacitors to be soldered on a particular graphic card ?
3.how many capacitors have to be soldered on the graphic card ?

thanks
post #2 of 8
1.- caps help to stabilize current/voltage supply and eliminate noise in the circuit- to the GPU and memory.. usually there are 2x sets of caps.. 1x set for input capacitance [12-16v] and 1x set for GPUv and vmem [2.4-6.3v]

2. - the 'uf' rating is the amount of microfarads the cap is rated to "hold" or "output".. the higher the number of 'uf' the greater the supply. The other numbers that are on a capacitor are the voltage which it is rated.

*you always want +1.5-6v OVER what you need..when it comes to 'sizing' voltage requirements for capacitors - ie = you need to add a 12v capacitor.. you should use a 16v cap then

3. -Adding caps is about "band-aids" ... in other words.. your not fixing anything physically broken.. your adding extra capacitance to the GPU where it needs it.. to help remain stable at higher clocks/voltages. Some GPU's have weak input phases.. making 16v caps help the most... other GPU's have weak output phases.. making 2.5-6.3v caps help the most [for GPUv and vmem].
post #3 of 8
Thread Starter 
^^sir again thanks....got it y to use caps ...but can u please tell me how can i detect that my gpu need caps to be soldered on it ? and how can i detect that my input phase is weak or output phase ? also how much microfarad caps have to be used on graphic card or it depends on gfx design ?
post #4 of 8
So capacitors pretty much clean up the volts so its constant instead of spiking?

And yeh when do you know if u need them or not
    
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post #5 of 8
Quote:
Originally Posted by Liighthead View Post
So capacitors pretty much clean up the volts so its constant instead of spiking?

And yeh when do you know if u need them or not
Yes.. and no..

Caps hold current for quick discharge, so voltage and current stay constant.. YES. ...but they also filter noise out of the circuit..which can ultimately lead to supply issues and unstable voltage as well.

Heres my method for determining what caps to add..


Set GPU clocks at highest stable limit at said voltage.. proceed to test with AA and AF enabled.. I use 3D'06 with full Q features and 1920x1080 res.

While testing - measure and monitor the +12v inputs on the GPU..measure at the PCI-E plug.. measure again at the first set of +12v caps. Note your results.

Repeat the above step- for the GPU output phases now.. measuring first at the inductor coils [both sides of the inductor... very important to have these measurements], then at the first set of GPUv output caps..and again at the back of the GPU core [if a suitable read exists.. it usually does ].

When done.. do the same process and focus on the vMEM circuit... inputs and outputs.

------------

Now look at your recorded results! Where is the biggest source of change? Where is voltage dipping or drooping the most? Consider a .2v drop through a circuit is "normal" ...anything beyond this needs improvement.

**The readings you take of the inductors are VERY important as this is often the best way to check for poor input supply.

ie- if voltage at the "input side" of the inductor coil reads 1.36v ... and the "output side" of the inductor coil reads 1.3... I will be adding +12v caps.

Changing inductors is probably the easiest way to prep a GPU for extreme use.. as it will help more than anything else, once you start approaching the limits of the power phases and capacitance on the PCB. Just examine the #'s on the inductor coil..and replace it with a larger value inductor. This step alone can bring +.5v to a GPU at the same GPUv setting..and push OCP up farther in the voltage range.
post #6 of 8
Thanks a heap bud keep this in mind
    
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post #7 of 8
Thread Starter 
again thanks sir ...u r awesome
post #8 of 8
Electricity is like water.
A wire is like a hose carrying water.
A capacitor is like a bucket with a hole at the bottom.

Sometimes this hose provides less water for a few seconds and this distruption will cause a pressure drop that screws up your work. Therefore, you install this bucket as a reservoir. Your hose will now fill the bucket first and you are getting water from the bucket's hole now. If there is a short-term, minor disruption, you are ok as long as there is enough water left in the bucket.

Get it?
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