How to Volt-mod your ATI Radeon videocard


All modifications described henceforth will void your warranty and if not done with proper care can result in rendering the product non-functional. Neither the author of this article nor TechSpot shall be held responsible for any injury incurred or hardware damaged when performing these modifications. Proceed at your own risk!


Some Background information

Quite contrary to our previously published GeForce4 volt-mod guide, Radeon boards found in the market are not very similar, better put, there is a wider component variance in the Radeon range of cards than in the GeForce 4 range, therefore this guide will be less specific than our first one; you might even be able to figure out how to volt mod your Geforce FX with this guide if you do some thinking on your own.

ATI has stayed true to producing small cards; take for example the Radeon 9600 which is similarly sized as their top of the line Radeon 9800 Pro. But make no mistake, even if one could assume that little differ between these, one would not be more wrong. Because the Radeon 9600 runs at lower frequencies those models are also equipped with power circuits that are not able to deliver as much “oomph” as the 9800. However if you look at the older, 9500 it does in fact use the same high-end circuit as the 9700 (later revisions had a scaled down power circuit though).

Things become even more fun (and complex) when we start looking at the VPUs. Radeon boards unlike GeForce4s do not share the same core. The lower-end 9600 models come with a .13 micron core that overclocks exceptionally well; the Radeon 9500 boards shares the same .15-micron core as the 9700; Then the 9800 uses a modified .15 micron 9700 core. Last but not least, there are also memory setups of varying sizes that draw different amounts of power and are rated for different nanosecond operation that you will need to keep track of.

There now I hope you are really confused, on top of that add customizations added by ATI’s many third party vendors and you soon have no clue what your card will be able to perform, this brings us to the next step…


Trial and Error

The only way to know how your particular card will overclock is by testing it, as simple as that. Then, when you run into a limitation you must first identify what is causing it and either fix it or decide that this will be “fast enough” and quit playing around before you end up with a dead card.


Overclocking before modifying

The first thing you must figure out is how far your card can be pushed before any modding, download your favourite overclocking program and give it a try. I use Powerstrip although you might prefer something simpler if you are only going to overclock.

Our victim was an Atlantis Radeon 9800 Pro board that we reviewed sometime ago, Sapphire was kind enough of leaving the card for us to play around. Right out of the box with no additional cooling this card’s memory would overclock from 338 MHz (default) to 366 MHz.

At this point it is quite reasonable to assume that the memory is running a bit hot, so I bought some standard sized Alpha heatsinks and cut them to fit and put on the memory modules. After I putting them on with some Arctic Silver Thermal Adhesive and let it set for the night my maximum memory overclock was up from 366 to 372 MHz. So now that I had reached the maximum memory overclock without volt modding I put my attention towards the core.

Since Radeon 9800s use the same .15-micron core as the old trusty 9700 I was not expecting to overclock it much, if at all. From the standard clock speed of 378 MHz, I reached a core speed of 421 MHz, to say the least I put my old thoughts about poor overclock-ability aside.


Go to next page !

Get weekly updates on new
articles, news and contests
in your mail!