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Palit 7900GS Review - Voltmodding
Graphics Cards
Written by Monkeyman   
Sunday, 22 October 2006 20:19
Article Index
Palit 7900GS Review
Overview and Specification
Packaging and Bundle
The Card
Gaming Performance
All Pages

Neither I or AOA take any responsibility for any damage or loss that may be caused through overclocking or modification of your equipment, you perform it at your own risk, however if you experience problems then we are happy to try and help you.

With that aside, let's begin.

The non-standard board design on Palit (and some other) 7900GS cards means that no conductive ink methods are necessary to increase the core voltage to the card, other brands can use modified BIOSes to increase the core voltage to 1.3v in 3D mode, on this card we can change it to suit our needs.

The resistor highlighted in the picture (just adjacent to the power input -Ed) is rated at about 620ohms, reducing the resistance of this will increase the core voltage of the card and hence increase the overclocking potential, what we have to bear in mind is that an increase in voltage is going to cause an increase in heat which the cards heatsink will have to be able to remove quick enough to prevent the card from overheating, artefacting or even failing entirely.

All you need to do to reduce the resistance is to get a sharp pencil and draw a gentle line from one end of the resistor to the other, using a multimeter check after each stoke to see how you are doing, when you reach your desired resistance then you can replace your card and see how much your overclocking potential increases, I recommend aiming to reduce it by 10ohms at a time, this way you can check temperatures each time and not overheat your card.

Through experimentation I discovered that reducing the resistance of the component to 600ohms which is around the 1.3v mark was the optimal level (no major increase in temperature but increased overclocking potential).

This is more than a 36% increase over the stock speed of the card, I discovered that by lowering the resistance to 550ohms (resulting in around 1.45v) I was able to achieve and overclock of 650MHz a staggering 45% overclock, however at this voltage temperature increased quickly and it was only stable for around 60 mins, however if you are willing to mod the heatsink to fit ram-sinks onto the card or to improve ventilation across the rest of the card then it is quite achievable.

It is worth noting that around the 650MHz mark I started to find the overall system was CPU limited so if you have a lower spec CPU than what was used in the test then it may not be worth aiming that high.

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