In our reviews we often overclock graphics cards in a “rational” way. In other words, we overclock without special tools or methods such as replacing the card’s native cooler with a liquid cooling system or modifying its power circuitry. One property of rational overclocking is that it can be continuously used in everyday operation. Although it often brings but small performance benefits, many gamers are interested in and practice this kind of overclocking.
Besides rational, there is extreme overclocking, which is quite a different thing. Such overclocking relies on extreme methods, up to cooling the overclocked card with liquid nitrogen or increasing the GPU and memory voltages in order to increase the overclockability of these components. As you know, nearly every GPU and memory chip can work at a clock rate far above the one set by the developer if you increase its voltage. Extreme overclocking leads to a sudden increase in the chip’s heat dissipation and a serious reduction of its service life. This explains why it is but seldom used by practical gamers. It is just a kind of sport in its own right in which record-breaking showings are more important than stable and problem-free operation. The excitement is high and so are the bets. Nearly every overclocker can tell you a story about how his graphics card died in the process of achieving a higher score in 3DMark. Some may even show you a whole collection of dead hardware.
It is flagship solutions that are usually overclocked in extreme ways because they give you the highest chance to set a new record you can boast about before other overclockers. We set ourselves a different goal in this review, however. We wanted to squeeze everything out of an ATI Radeon HD 3870 to check out the potential of the RV670 chip and see if it could at least theoretically be as fast as Nvidia’s G92-based solutions. It is an interesting question because there is currently a gap in the Radeon HD 3000 line-up between the relatively inexpensive single-chip Radeon HD 3870 and the dual-chip Radeon HD 3870 X2 whereas there is no such gap in Nvidia’s line-up.
True overclockers often limit themselves to fixing the record in 3DMark. We are not in for any records, yet we hope to achieve a GPU frequency of 1GHz with air cooling and test our Radeon HD 3870 in this mode in our traditional benchmarks. This will provide a complete picture of performance that may be interesting for ordinary gamers, not only overclockers.
Our experiments should not be understood as an invitation to overclocking or modifying any hardware. Everyone who wants to repeat them will do so at his own risk.
