Overclocking The GeForce 2 GTS

The GeForce 2 GTS GPU

The GeForce 2 GTS, announced April 26th and available in cards very shortly thereafter, is essentially the GeForce 256 GPU produced on a .18 micron die with increased speeds and additional features (for more information, see our NVIDIA GeForce 2 GTS reivew). There is no question that the new GPU offers speed increases over the GeForce 256, but where does this speed come from. Well, the majority of speed increases that we see in the GeForce 2 GTS come from the increased clock speed and the enhanced texture pipeline.

By shrinking the architecture of the GeForce GPU down from .22 micron to .18 micron, NVIDIA was not only able to shrink the amount of silicon used in the GPU, but also to increase the speed at which these transistors operate at. Shrinking the GeForce 2 GTS GPU by using a 0.18 micron fabrication process resulted in a chip that runs significantly cooler than the .22 micron version. The reason for this is simple: by decreasing the size of the transistors in the chip, voltage, current, and thus power were also decreased. By decreasing these elements, heat associated with the items are also decreased. As we all know, heat is the enemy because it decreases the operational range of the transistors inside a processor. For example, if we have a .5 micron chip that dissipates lots of heat, the heat will render the transistors inside the chip useless because they simply can not operate at such a high temperature. By reducing the architecture of the GeForce 2 GTS GPU to .18 micron, NVIDIA has essentially eliminated harmful heat from the problem because at the stock speed of 200 MHz the processor does not produce enough heat to hinder the performance of the GPU. The MHz of the core clock is what determines theoretical fill rate, as the card would go x amount fast if it had nothing limiting its performance, which we find out is not the case in the next section.

The second item that increases the performance of the GeForce 2 GTS GPU over that of the originally GeForce 256 is the texture pipeline that the GeForce 2 GTS employs. Both GPUs contain a four pipeline rendering engine, however the GeForce 2 GTS improves upon the original GeForce 256 by processing two textures per pipeline in a single clock. The GeForce 256 could only process one texture per clock in each of its four pipes. This results in the second aspect of the GeForce 2 GTS's power: while the GeForce 256 can only process four textures per clock, the GeForce 2 GTS can processor eight textures in a single clock tick. This results in the GeForce 2 GTS being able to have twice the rendering power of the GeForce 256 at the same clock speed.

Both of the new aspects that significantly increase speed in the GeForce 2 GTS also significantly alter its overclocking nature. Besides increasing the raw speed of the card, these features also produce a new challenge for overclocking.