The highly anticipated GeForce 7800GTX chipset from Nvidia is currently implemented in various VGA kits (AOpen, Gainward etc), and the first benchmarks indicate impressive performance although full throttle operation seems to require excessive processing power from the CPU.
The Nvidia GeForce 7800 GTX is based on the architecture of the GeForce 6 series. However, specific enhancements made on the 7800GTX are expected to boost performance to the limits. Below you can see a comparison of the new 7800GTX with the previous Nvidia model, the Geforce 6800 Ultra, announced last April.
GeForce 7800 GTX
GeForce 6800 Ultra
|GPU clock||430 MHz||400 MHz|
|Video Memory||256MB (GDDR3)||256MB (GDDR3)|
|Shader engine||Cine FX 4.0||Cine FX 3.0|
|Anti-aliasing technology||IntelliSample 4.0||IntelliSample 3.0|
The differences are obvious. First of all, the 7800GTX GPU was built on the 0.11μm manufacturing process. This process had also been used for the GeForce 6600 and 6200 series.
Both core and memory clocks have been improved. On the other hand, the memory has been kept to 256MB.
What is expected to make the difference is the adoption of a new shader engine and Antialising technology. The number of pixel rendering pipelines has been increased to 24 and the shader units increased to 8. Combined with the Cine FX 4.0 shader unit, the card is expected to deliver almost two times (2x) the shading power of previous generation products taking gaming performance to extreme levels. In addition, the Microsoft DirectX 9.0 Shader Model 3.0 support promises high performance for all DirectX 9 applications, including Shader Model 3.0 titles.
The upgraded IntelliSample v4.0 is also expected to provide high visual quality through gamma correct rotated grid antialiasing and advanced anisotropic filtering. The improved sample coverage (up to 128 Taps) improves the quality of anisotropic filtering.
The substantial cooling required by the 7800 GTX are provided by the heat sinks, coupled with a cooling fan, as you can see in the picture above. The first tests indicate that the cooling system is adequate and keeps the GPU's temperature at low and safe levels, even under the demanding SLI configurations. Another "plus" for this graphics card is that it does not have a heat sink on both sides, allowing easier installation in the crowded PCI slots of a PC.
However, the power consumption when connected in SLI mode is higher than when in single use. Although Nvidia reports that the total power consumption for the card is 110W, a 500W power supply (12V, 30A line) is recommended.
Another great feature of the display card is its support for the SLI technology. The card delivers almost two times (2x) the performance of a single GPU by allowing two graphics display cards to run in parallel.
Video processing is enhanced through the adoption of Nvidia's PureVideo technology. Moreover, the card conforms to the HDTV(1080i) output.
CDRinfo will present a detailed review of the GeForce 7800GTX VGA card sometime in the near future. As a first comment, we might say that this impressive piece of hardware does make a performance difference when connected as a single VGA card, but it requires huge CPU resources when connected in SLI mode. A direct comparison with the upcoming CrossFire from ATI hosting the R520 chipset seems to be essential, and hopefully will be presented here soon.