GeForce FX 5900 Ultra in Detail
nVidia is aiming to remedy all of the problems of NV30 core with the new FX 5900 (NV35) series. Obviously, this is not a completely new design, but a lot of details have been changed and improved.
The NV35 is built on the .13 micron process just like the NV30 and NV31. We do get a few new buzzwords with this release, CineFX 2.0 and Intellisample HCT, which we will go over a bit later. There are a few big improvements for the NV35 over the NV30. The hardest hitting change is the use of a 256-bit memory bus. You will recall the ATI Radeon 9700/Pro and 9800/Pro already uses a 256-bit memory bus. Now the NV35 utilizes this bus width as well, allowing for much more bandwidth to be processed when compared to the NV30. Another addition is the use of 256MB total video card RAM on the high end GeForceFX 5900 Ultra board. This added memory will give you more room for framebuffer functions such as resolution and AA settings combined with texture storage.
The GeForce FX 5900 Ultra ships at an 850MHz DDR memory speed on a 256-bit memory bus, which produces a total of 27.2GB/sec of raw memory bandwidth. That is a 70% increase in raw memory bandwidth over the GeForceFX 5800 Ultra and 21% more raw bandwidth when compared to the ATI Radeon 9800 Pro 256MB. However, this is still a 4 pixel pipeline card.
Many gamers and definitely all hardware testers will be relieved to know that the new cooling solution sounds a lot less like a vacuum cleaner and operates at a much more bearable volume.
- Ultra Shadow
CineFX 2.0 is the name given to the cinematic quality part of the NV35. This is where the 2x increase in shader ops comes into play as well as the Ultrashadow technology and 128-bit internal precision.
Ultrashadow is nVidia's name for a new routine in the NV35 to help accelerate shadow volumes. As you know, shadow volumes will be a big part in Doom III, and any card that wants to compete with the big boys will need to be able to handle these extensive stencil shadows very efficiently. The easiest way to think about Ultrashadow is simply to visualize that the card is not calculating shadows that cannot be seen by the camera. Meaning that shadows behind an object on your computer screen, or out of view of your character (or you), are not given to the GPU to figure out. Therefore, the 5900 Ultra is not doing work that needs not be done, giving those saved GPU cycles for other priorities.