The performance of the GeForce 7800 GTX was compared to the GeForce 6800 GT running in an SLI configuration. I had planned on including performance from a single GeForce 6800 GT, but the review deadline was quickly approaching. This was unfortunate since it would have been an even more effective demonstration of how powerful the GeForce 7800 GTX is.
Reference GeForce 7800 GTX
Click Image to Enlarge
The GeForce 7800 GTX almost spans the length of the Asus A8N-SLI motherboard, which ends where the white bar-coded sticker is located at the far right.
Power Supply Requirements
It is critical that systems with high-end graphics cards, such as the GeForce 6800 Ultra and GeForce 7800 GTX, are matched with an adequate power supply to ensure stable operation. Therefore, I have provided the following power supply information, which originated from NVIDIA's GeForce 7800 GTX GPU Reviewer's Guide:
The GeForce 7800 GTX requires a stable, 12-volt power source for best performance, reliability, and enjoyment. Many PC power supplies dedicate most of their 12-volt power to the power rail that goes to the CPU, rather than the peripheral connectors. Many power supplies also do not provide ample overload protection to protect system components such as motherboards and graphics cards.
For a SINGLE GeForce 7800 GTX graphics card, NVIDIA recommends a power supply with at least 350W, 22amps on 12V. For a DUAL SLI GeForce 7800 GTX graphics configuration, NVIDIA recommends a power supply with at least 500W, 30 amps on 12V. A list of SLI-certified power supplies can be found at SLIzone. Due to power distribution limitations of the PCI Express bus, GeForce 7800 GTX boards require a separate PCI Express power plug on the back end of the card.
AMD Athlon 64 4000+ Processor
Asus A8N-SLI Deluxe Motherboard
Corsair XMS 3200 Memory Model 3200LLPRO - (2) 512MB DIMMs - 1GB Total
Western Digital Raptor 74GB HDD (1), 10000RPM, 4.5ms Avg Seek, 8MB Buffer, SATA
Western Digital Caviar 80GB HDD (2), 7200RPM, 8.9ms Avg Seek, 8MB Buffer, ATA-100
Vsync Disabled / 75Hz Refresh Rate / 70Hz at 1920x1440 / 60Hz at 2048x1536
Windows XP Professional with Service Pack 2 / DirectX 9.0c
Doom 3 - v1.0.1282
Far Cry - v1.31 (Build 1378)
Half-Life 2 - v18.104.22.168
Splinter Cell Chaos Theory - v1.03
All applications tested were patched to their latest version with the exception of Doom 3.
Fraps was used to capture the minimum frame rate in some benchmarks.
The predefined multichip rendering mode as defined in the application profile was always used when running in SLI mode.
ANTIALIASING IMAGE QUALITY
The GeForce 7800 GTX features gamma corrected antialiasing and the ability to antialias objects that are constructed using transparent textures, which is a popular technique to render trees, branches, grass, and chain link fences. Multisampling antialiasing does not affect these types of objects since they are embedded within a polygon while supersampling antialiasing has a limited effect on transparent textures. NVIDIA refers to their new antialiasing technique as transparent adaptive multisampling or transparent adaptive supersampling depending on the method selected in the driver control panel.
New Antialiasing Features
The default image contains yellow and white numeric labels that indicate areas in the scene where image quality improves as a particular feature is enabled. The labels correspond to the links underneath the image, which contain a number in parenthesis next to each image quality enhancing feature. For example, the labels containing the number 1 illustrate areas in the scene that improved when texture filtering was changed from trilinear to 8X anisotropic. Labels numbered 3 indicate areas that improved when the level of antialiasing was increased from 2X to 4X (with anisotropic filtering remaining at 8X).
Clicking on a link under the image will download the corresponding image (~120KB) from the server, which will be saved in your browser cache. After all of the images have been downloaded and saved, you will be able to quickly switch between them using the links below the image to see the differences in image quality. As you switch between the images, the changes, some of which are subtle, will occur in the areas marked by the labels.
Note: To benefit from this image quality analysis, position your eyes about 12 inches from the monitor as you compare the images being presented by the applet.
A significant portion of the time I worked on this preview was devoted to this image quality comparison. There was no doubt that it was necessary after having witnessed the benefits of supersampling transparency adaptive antialiasing!
Notice that the image quality did not change when multisampling transparency was enabled. In this case, it is due to the specific type of texture being used in Half-Life 2. Supersampling transparency however, was designed to operate on a broader range of transparent textures.
Transparent Adaptive Supersampling Performance
In Half-Life 2, the performance hit associated with gamma correction and transparent adaptive supersampling was minor. The following results were obtained at a resolution of 1280x960 with 4X AA and 8X AF enabled. The driver Image Setting was set to High Quality and the highest-quality graphics options were enabled via the in-game menu. Doom 3 was run at 1024x768 with 4X AA and 8X AF with High Quality settings.
3dnews_canal - from 97 to 93 fps
at_c17_c12 - from 82 to 80 fps
at_canals_08 - from 105 to 101 fps
There was no impact on performance in Doom 3, which indicates that the transparent adaptive algorithm applies antialiasing to the appropriate textures as needed.