I PURPOSE OF REPORT This report will compare Voodoo5 5500 with NVIDIA’s Geforce2 Ultra to determine which accelerator provides the best performance. Both companies’ accelerators share the same goal, to bring the highest visual quality possible.
Although both companies share the same goal, their approaches are extremely different. Cost will also be addressed. The following features will be examined: – Dual 3dfx VSA-100 – T-Buffering – Fill Rate – 32-bit Z-Buffer/Stencil – Synchronous dynamic random access memory – 32-bit Color II 3D IMAGING 3D objects are created by connecting two-dimensional polygons. Objects appear to be 3D dimensional because the computer calculates the necessary angles to give the illusion of depth. The computer then assigns a give texture to each object, textures are the covering of the object. Like in the real world, different textures have different properties, like color, luster, opaque, etc. These objects are then displayed on the computer’s monitor. Many 3D objects can be combined to create a 3D environment.
A 3D environment is the computers generation of a make believe world. When the camera, the point of view within the 3D world, moves, the computer calculates the height, width, depth and the lighting of every object and adjust them in way that from the perspective of the camera, you appear to be moving within the environment. What is 3D? The first dimension is a line. The second dimension, a plane. This world is described vertically and horizontally. This is what you draw on a piece of paper.
The third dimension, our dimension, allows free movement and perception by adding depth. This allows movement in all directions, up, down, left, right, forwards and back. All personal computers come pre-installed with a two-dimensional (2D) graphics board – the hardware that creates the computer screen graphics for flat applications like Microsoft Word and Excel. But, to make 3D images in real-time (or on-the-fly), a computer must make millions of complex mathematical calculations every second. This can make games and 3D graphics applications slow and jerky as the computer gets caught up rendering 3D images in addition to running the program. 3D accelerators solve this problem. When you install a 3D accelerator, the 3D graphics previously rendered by the CPU (your computer’s processor) are now rendered by the 3D accelerator. This significantly increases the performance, visual effects, and drastically improves the 3D experience.
III VOODOO5 5500 The Voodoo5 5500 is 3Dfx’s latest 3D accelerator. The card features dual 3dfx VSA-100 chips, Real-Time Full-Scene HW Anti-Aliasing, the exclusive T-Buffer Digital Cinematic Effects engine, Z-Buffer/Stencil, 32-bit Z-Buffer/Stencil, 64MB of graphics memory, 32-bit color. Dual 3dfx VSA-100 3D objects are broken down into primitive polygons using triangles. The 3D processor(s) then use primitive polygons to perform calculations (Z-Buffering, FFSAA, etc.
) The Voodoo5 5500 duel VSA-100 chips are able to process 11 million triangles a second. T-Buffering Basically, T-Buffer technology renders numerous copies of the same scene. The copies are then merged and output to the video. This process dramatically increased the quality of the images displayed. They appear smooth without spatial artifacts . Most 3D cards on the market use some form of FSAA but the 3Dfx’s T-Buffering has other important features like depth-of-field blur.
When humans look at things, our eyes focus on the object that we are looking at and not its surroundings. This is why in real life, the only object we can truly see clearly is the object focussed on. In current 3D games, however, there is no “depth of field”; everything is rendered with perfect clarity regardless of how close our virtual “eyes” are supposed to be. Currently many game developers deal with this issue by using a fog effect, so objects that are farther away are blurrier. However, this does not look real since the fog obscures and fades the colors of the distant. With the T-buffer, depth of field is a reality, making rendered images much more realistic. The T-Buffer has two other abilities: soft shadows and soft reflections. Shadows and reflections in frames that pass through the T-Buffer look more realistic.
Voodoo5 5500 uses T-Buffer Digital Cinematic Effects engine smoothes motion and improve image quality or to exaggerate motion for special effects.” This technology powers the card’s most important attribute, Real-Time Full-Scene Hardware Anti-Aliasing (FSAA). Full-Scene Anti-Aliasing (FSAA) is the removal of aliasing artifacts. Aliasing artifacts come in two forms: “jaggies,” or stairstepping of diagonal lines, and flashing or “popping” of very thin polygons. These spatial artifacts occur because the scene being rendered is under sampled.
Full-scene anti-aliasing smoothes the jagged lines and eliminates the scintillating of very thin objects by taking many samples of the scene and blending them together. The result is a much smoother, far more realistic and pleasing image. In order for this technology to deliver the best image quality, each image must have 16-30 copies scent through the T-Buffer. Unfortunately with the processor on the card this is not possible. It requires too many times more fill-rate and geometry and triangle processing power than is now available. 3dfx’s current T-buffer uses many fewer passes (somewhere around 4) to keep within an acceptable frame rate. Without the full 16-30 passes, however, discrete images of reflections/motion blurs may be observed, rather than smooth transitions. Fill Rate The Voodoo5 5500 has a fill rate of 667MegaTexels.
Fill rate is the number of texels that can be rendered per second. A texel is the smallest graphical element in a two-dimensional (2-D) texture mapping used to “wallpaper” the rendition of a three-dimensional (3D) object, creating the impression of a textured surface. The fill rate is directly related to the frame rate or the frames per second. In order to achieve the best 3D experience, both a high fill rate and a high frames per second are needed. This report will examine the Voodoo5 5500’s frames per second later on. 32-bit Z-Buffer/Stencil Like many other 3D cards the Voodo5 5500 features 32-bit Z-buffer/stencil.
In order to understand Z-Buffering, you first must possess a basic understanding of Z-Sorting. In order for the computer to give the illusion the computer must calculate which objects should appear to be behind other objects. In Z-Sorting the computer’s rendering engine sorts each polygon from back to front based on its theoretical position on the Z-axis. The computer then draws each object from back to front, objects with a closer Z-axis to the camera overlap objects behind them, creating an image of depth. Z-Buffering is a faster alternative to Z-Sorting. A depth value is assigned to ever pixel that makes up the surface of an object.
Pixels that are closer to the camera are assigned lower values while pixels that are further away from the camera are assigned higher values. Before the computer draws a new pixel, the pixel’s depth value is compared with the depth values of the other pixels that share the same coordinates (position on the screen). The pixels are only drawn if they have lowest depth value, meaning that they are closer to the camera. Z-Buffering/stencil ensures that unnecessary pixels, (pixels that would be blocked by a pixel of another object) are not drawn. Synchronous dynamic random access memory (SDRAM) The Voodoo5 5500 has 64MB of Synchronous dynamic random access memory (SDRAM) with a clock speed of 166MHz. Synchronous DRAM (SDRAM) is a generic name for various kinds of dynamic random access memory (DRAM) that are synchronized with the clock speed that the microprocessor is optimized for.
This tends to increase the number of instructions that the processor can perform in a given time 32-bit Color The Voodoo5 5500’s dual 3dfx VSA-100 chips support full 32-bit color accuracy, meaning that is can display approximately 32 thousand different colors on your monitor. The dual VSA-100 chips are able to deliver a maximum 2D rendering ability 2048 pixels by 2048 pixels, displaying amazing detail of 2D images. IV GeForce2 Ultra The GeForce2 Ultra Graphics Processing Unit (GPU) is NVIDIA’s latest 3D accelerator.
The card features a 250MHz GeForce processor, 64MB of Double Data Rate (DDR) SDRAM running at 230MHz (giving an “effective” clock speed of 460MHz). 250MHz GeForce 250MHz GeForce processor can render 31 million triangles per second . Fill Rate The GeForce2 Ultra has a fill rate of 2 GigaTexel’s per second . FSAA GeForce2 Ultra uses FSAA technology.
The GeForce2 Ultra’s use of FSAA does not include a T-Buffer and does not offer depth-of-field blur, soft-shadows or soft reflections. The GeForce2 Ultra does include a feature like to Z-Buffer to increase realism, the feature is called transform and lighting (T;L). How does transform work? Transform performance dictates how precisely software developers can “tessellate” the 3D objects they create, how many objects they can put in a scene and how sophisticated the 3D world itself can be. To tessellate an object means to divide it into smaller geometric objects, such as polygons. The images below are examples of a sphere tessellated by different degrees: Each of the images above represents the same sphere, but the image on the far right is clearly the most realistic of the three. It has been carved up into five times as many polygons as the sphere on the far left, and therefore requires five times the transform performance as the sphere on the left. That may not seem very important for one sphere, but because hundreds to thousands of objects are often displayed in scenes, without a GPU those objects have to share the limited processing power of the CPU, forcing software developers to budget processing tasks. Now with an NVIDIA GPU transform calculations are offloaded from the CPU, allowing more detailed objects with higher polygon counts to be processed more quickly.
With transformation a jungle scene can have lots of trees and bushesrather than just a single treeand each tree can consist of many leaves created by thousands of polygons. Since the GPU relieves the CPU of the burden of calculating the transforms, you will be able to view scenes rich with complex objects that look real and move like their real-life counterparts. Not only will the objects and characters be complex, but many more can exist.
How does lighting work? The human eye is more sensitive to changes in brightness than it is to changes in colorwhich means that an image with lighting effects communicates more information to a viewer more efficiently. The discrete lighting engine on an NVIDIA GPU calculates distance vectors from lights to objects and from objects to a viewer’s eyes within 3D scenes. Lighting calculations are an effective way to add both subtle and not-so-subtle changes in brightness to 3D objects in a manner that mimics real-world lighting conditions. 32-bit Z-Buffer/Stencil The GeForce2 Ultra uses 32-bit Z-Buffer/Stencil technology . Double Data Rate The GeForce2 Ultra most notable feature is its speed. The card features 64MB of Double Data Rate SGRAM (DDR).
DDR allows for data to be fetched on both the rising and falling edges of the clock thus doubling the effective transfer rate of the clock, the ability at which the memory is able to collected by processor. The 64MB of DDR has a clock speed of 233MHZ, but because of it’s ability to send information on the rising and falling edges of the clock it really has a clock speed of 466MHz. 32-bit Color 250MHz GeForce processor supports full 32-bit color accuracy. 250MHz GeForce processor has a maximum 2D rendering ability 2048 pixels by 2048 pixels. Analysis Both cards are powered by different technologies and different chip sets but with the same fundamental goal: to give the best 3D experience possible. The best 3D experience is when you run at a very high resolution with a very high fill rate and with a large number of frames per second (over 60 frames per second (fps) is ideal).
In order to determine which card is superior both are installed on identical computers. Each card runs the same 3D program while measurements are taken at different resolutions. The attached charts compare the two 3d accelerators at different resolutions. The charts demonstrate the frames per second at different resolutions. At higher resolutions the GeForce2 Ultra is a smoother performer and provides a more realistic 3d experience. VI CONCLUSION The GeForce2 Ultra outperforms the Voodoo5 5500 in all aspects. VII COST Retail cost for the two accelerators in Toronto, Canada (in Canadian dollars)is: GeForce2 Ultra: $639.
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