The core (cont’d)

Pixel pipelines

Besides the new memory controller, the GeForce FX 5700 Ultra core sports many changes. Remember, we’re dealing with a cost-reduced version of the NV35 core here, so NVIDIA is basically passing all of the new technologies first introduced in its latest flagship product down to the mainstream consumer. The only difference is performance, to ease manufacturing costs NVIDIA reduced the GeForce FX 5700/5700 Ultra to a 4x1 pixel pipeline architecture, GeForce FX 5900/5950 is a 4x2 design.

As a result of the changes, GeForce FX 5700 is composed of approximately 82 million transistors (versus 130 million in NV35); this is a slight increase from the 80 million transistors in GeForce FX 5600.

The core itself operates at a clock frequency of 475MHz, an increase of 75MHz from the GeForce FX 5600 Ultra, but 25MHz shy of the RADEON 9600 XT’s 500MHz core clock speed. This gives ATI a slight advantage in peak theoretical fill rate 2.0 Gigatexels/sec versus 1.9 Gigatexels/sec in GeForce FX 5700 Ultra.

New manufacturing partner

The GeForce FX 5700 is also the first NVIDIA product to be manufactured by IBM. NVIDIA previously relied solely on TSMC’s foundries. NVIDIA plans to continue its relationship with TSMC, but IBM will also be rolled into the mix, giving NVIDIA two manufacturing partners. It’s expected that NVIDIA’s next-generation part will also be manufactured by IBM. GeForce FX 5900 and 5950 cores will continue to be manufactured by TSMC.

Like the GeForce FX 5600, the GeForce FX 5700 is built on a 0.13-micron manufacturing process with copper interconnects, but IBM spices up the formula by fusing low-k dielectric material to the combination. As we mentioned in our RADEON 9600 XT article, low-k dielectric shields the copper circuits within the graphics core from each other, preventing electrical crosstalk from occurring. This allows NVIDIA to increase core clock frequency without wasting power. One interesting tidbit we picked up while talking with NVIDIA about the new IBM process is that they were able to go straight into full production from first silicon, just like NV35.

Features

Since the GeForce FX 5700 is based on the GeForce FX 5900/5950’s roots, you’ll see all of the same fundamental technologies incorporated in those cores integrated into the GeForce FX 5700 as well. This includes NVIDIA’s UltraShadow technology. UltraShadow is designed to improve performance when shadows are used extensively. The technology works by limiting all lighting calculations to specific areas that are predefined by the game developer, allowing the shadow to be rendered more quickly and with greater efficiency. We like to think of it as occlusion culling, but exclusively for shadows.

NVIDIA has also adopted the new compression algorithms in its Intellisample HCT technology into GeForce FX 5700. This should result in improved anti-aliasing performance at high resolutions. Finally, NV35’s CineFX 2.0 enhancements have been included. This allows pixel shader programs to be executed more quickly, enhancing shader performance. We’ll put this theory to the test first.