Saturday, April 11, 2009
Two different parts of a video card may be overclocked, the GPU (Graphics Processing Unit)and the RAM. In addition, disabled pipelines on a video card may also be enabled throughthird-party drivers, third-party software, or direct hardware modifications depending on yourvideo card type. Overclocking a video card is usually done through third-party or proprietarysoftware.Recent ATI proprietary Catalyst drivers feature an interface called Overdrive that allows fordynamic GPU frequency scaling based on its temperature and load. Increase the load, the clockrate increases for performance, but it's balanced against the increasing temperature. Sufficientfor simple increases in overall performance, but doesn't allow for the best performance increasewhich requires overclocking the memory. For this you need third-party applications or drivers.An example is ATITool. This program has many options, including GPU and memoryoverclocking, temperature monitoring, and fan control allowing for a much more completesolution to overclocking ATI based video cards. As for example drivers, for ATI there aremany, omegadrivers.net is one of them, also hosted there are nVidia drivers as well. Both ofwhich include integrated overclocking and many unlocked features, even including enhancedimage quality for nVidia-based cards. nVidia video cards can also be OCed through a hiddenfeature in the driver called coolbits.The most important thing to remember about overclocking a video card is cooling. This can't be44stressed enough. Just the same as a CPU can be damaged or have a shortened lifespan byoverclocking or excessive and prolonged heat, so can a video card. In the past year manyinexpensive and easy to install options have surfaced for cooling a video card, from adhesiveram heatsinks to attach to un-cooled ram chips, to rather expensive water-cooling solutions. Agood midpoint (both in cost and effectiveness) solution is to purchase and install a directexhaust, "sandwich" cooling solution. Direct exhaust means all air from the cooling fan isblown across the video card and directly out of the computer case, usually using the open PCIslot below the AGP (or PCIx) slot. This allows for substantially lower GPU temperatures. Asandwich cooler is two aluminum or copper heatsinks, shape formed for a particular video card,that "sandwiches" the video card in between the two and are usually connected by some kind ofcopper heat pipe which allows for the hotter side to convey heat to the cooler side fordissipation. The GPU should never surpass 60 degrees celsius for optimal performance and toavoid damaging the card. Most of the latest video cards are rated to go up to 90c, but this isNOT recommended by anyone. The optimal temperature for a video card is 40-55c for the carditself (the GPU's temperature differs depending on which you have,) but the lower you can getit, the better.One important thing to note. Many think that the option which says "AGP voltage" in theirBIOS can be used to "voltmod" a video card to get a bit more power out of it. In fact, it's usedfor something else, and raising the AGP voltage can and probably will cause damage to a videocard.