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Shammy 09-29-2009 11:41 AM

Souping Up your VGAs
Ok so maybe you think about souping up your VGA. Here’s a general example of a way.

This is NOT a 5870 VMod guide, just using techpowerup’s clear picture to explain in general!

Ok so first you wanna identify the power regulation areas. So First look for inductors aka chokes.

There are usually many around some are input inductors some output. To identify which are inputs (your +12v) which outputs (your memorys, cores) you can first check the caps beside or very near it. So say in the example the inductor on top left is beside a 16v rated cap (its written on it 16v). So maybe its input. So you just do a continuity check with DMM on either side of the inductor legs and the positive side of the 16v cap. The positive side is without line, with line = negative. So you find its connected. So that means that it is input inductor. Input Caps you usually see +16v ratings, Output caps for core you usually see 2.5v ratings, output caps for Memory you usually see 6.3v ratings, maybe sometimes 2.5v.

Or you can also measure the voltage at the inductors leg either one when VGA is running and you can see if input or output. Ok so you separate the input and output inductors in the picture.

So basically you wanna take care of output first since that’s whats going into your core or memory. So we look at the red boxes.
So we take a look first at the lone inductor on top left.

We see some MLCCs multilayer ceramic caps beside it. So are these the caps for this particular output power? So we use a DMM to check continuity between both ends of cap and the either legs of inductors. One end of cap will be the positive the other end will be the negative connected to ground. So ok we find the caps one end is directly connected to this inductor. Ok so time to add some caps. Now usually you want enough MLCCs to filter off small spikes and normal caps to filter off larger spikes. Usually it’s sufficient to add normal caps since there is usually a lot more MLCCs used in VGA Cards but you can add a mix if wanted. When you add MLCCs you don’t need to worry about polarity.

Usually in a single phase example power above, adding 2 x 500+uF caps is more than sufficient. Adding caps is just stacking them in parallel to existing ones. In the example, you just pick two of the present MLCCs, solder the positive leg of cap to the positive end of cap (the end that is connected to the inductor) and negative leg of cap to negative end of cap or any grounded pad.

Do not solder negative to positive end and vice versa! Be generous with solder to get ample surface area contact (BUT NO Shorting make sure!) to get the actual benefit. Check after soldering to make sure that positive is positive and negative is negative and no shorting between the 2. For what voltage rated caps to use, if lazy just use 16v caps, but better just to measure the voltage this power reg gives. For example it’s a voltage to the core of 1.2v then you can pick a 2.5v cap. If a voltage to the Memory say 1.80v then probably a 6.3v cap.

Ok so then do similar to the other output powers:

Like a 4 phaser above you can just throw in 4 to 5x 500+UFs. You can also even solder to bare pads like the above.

The picture above looks like a 2 phase solution but you don’t see a single controller for this reg nearby. So you check the continuity between the 2 inductors, and you find there are actually separate single phases. So then you repeat the process of adding Caps.

Ok so now, you’re done souping up the output.
So we look at input. Input comes from the pcie slot and the 6/8 pin pcie connectors.

It is better to add caps for input closer to the mosfets that they supply to. Not that important but more important to increase the input threshold by solder power connectors for +12v of your PSU. Input power is first limited by the power connectors surface contact and then next by the inductor that passes this current, so it is best to solder your THICK connection wires AFTER the input inductor. This can be at the mosfet input caps or the leg of the inductor that is closer to the mosfet side. The problem with soldering to the leg of the inductor closer to mosfet side is that you don’t know which leg exactly unless you remove the inductor to check or look at the plane sketchings. The not so good aspect of soldering wire to the caps is that unless you dab a big blob of solder to the ends of various caps, you may not get a lot of contact surface.

So first you need to separately identify the +12v input from the slot vs the power connectors as each is isolated and many power supplies don’t like it if you connect different rails together or worse connecting +12vs of 2 PSUs together if you use a separate PSU for the VGA.
First find which power source the slot gives by doing continuity check with the pin on the pcie

Then you may find one or two input inductors for this:

Ok so you can solder one or two molex connectors to the card at the appropriate leg of inductor, with the yellow +12v wire there of course:

Logically if the current flows in from below, it would make more sense to route it to go in at the lower leg of inductor and exit the higher leg of inductor so we can pick that 2 red ends to solder to.
Then you want to of cos solder the black wire of the molex to a grounded spot of sufficient surface area such as a big capacitor’s negative end.
So then you will use the molex of your mainboard’s power supply to connect to this/these molexes.

So that just leaves the 2 power connectors. By doing continuity checks again you see each connector’s input inductor:

So time to whip out the free cable convertors that come with your VGA and cut them up and use them.
This time let’s solder the yellow +12v to the caps.
Black wires of the connector to the negative ends of caps or the 6 pin pcie connectors ground pad.

Then… OK!!!!
You prolly need a hot soldering iron , and a fatter tip for some of these so invest in a good one with adjustable temps.

k|ngp|n 09-29-2009 11:47 AM

Oh..Listen up to da man! Hot air station helps too :D

ocgmj 09-29-2009 11:52 AM

Excellent info! :up:

FatAlbert 09-29-2009 03:29 PM

so who will do sham's radeon ? :D:D

hiwa 09-29-2009 03:46 PM


387X ?

:D:D sham and Old ati

Great infos peter thanks :up:

Gatman 09-29-2009 05:18 PM

Thanks so much for this. Much better than mod guides that show but don't tell...and worse still some threads where people go "well, I stuck these caps here but I don't know why".

I'll forgive you for your loose RTL now. :p

chispy 09-29-2009 06:21 PM

Excellent info Shammino , Thanks for sharing this information, much appreciated.


Shammy 09-29-2009 10:22 PM


Originally Posted by Gautam (Post 1894)
I'll forgive you for your loose RTL now. :p

noooooo i knew it! i shoulda just keyed in some whacky numbers like 30!!!

crustytheclown 09-30-2009 05:17 AM

Great info Shammy...thanks alot!!!

IllusioN OC 09-30-2009 07:07 AM

.., cast iron clamp holding evap in place in second pic is soooo brutal... :-)

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