The 8800 – An Overview

The 8800GTX (and GTS) is the world’s first GPU to fully support DirectX 10. The 8800 GTX features 128 stream processors which run at 1.35GHz. Each of these stream processors is fully programmable and can be dynamically allocated (GigaThread Technology) to perform traditional vertex and pixel operations as well as geometry and physics calculations. As the 8800 was specifically designed for DirectX 10 it supports the API’s unified shader instruction set and Shader Model 4.

Nvidia are calling their image quality technology the Luminex engine and this feature is arguably one of the most important aspects of the product. For some time now ATI have been able to claim preferable Image Quality due to the lack of shimmering in games and the ability to use Anti-Aliasing and HDR lighting at the same time in titles such as Oblivion. It could also be said that ATI’s enhanced AF and AA modes provided superior quality when compared to Nvidia’s methods used in the previous generation.

The first thing we can say about the 8800 series is that AA can now be used with HDR (128bit precision, 32-bit floating point) and we shall look at this further in the IQ and Oblivion sections of the article. There are additional improvements such as the availability of 8x and 16x AA on single card systems and angle-independent anisotropic filtering.

The new AA modes are available in addition to the traditional AA modes and use both geometry and coverage sampling anti aliasing. (CSAA) The claim from Nvidia is that their 16xCSAA mode should perform similarly to traditional 4xmulti sample AA. Available through a control panel option entitled Angular LOD control we are able to increase the Anisotropic filtering quality (select High Quality) by disabling angular optimisations and as a result delivering near perfect Anisotropic filtering. Later in the article we shall look at the performance and Image quality impacts of the new AA and AF modes available on the 8800 series.

In addition to the enhanced AA and AF technology Nvidia have also enhanced the overall architecture of their new cards to a 10-bit architecture which in conjunction with the 10-bit DACSs allow the product to display over a billion colours, the previous generation of products supported 16.7million colours.

We mentioned above that the 8800 series is capable of physics computations and that it features 128 stream processors which can be utilised for this task. As well as allowing game designers to improve the quality of smoke, explosions, fur, hair and so on the ability to perform physics work on the GPU means that CPU resource can be freed up to concentrate on the game engine and AI. When combined with a quad core CPU and correctly coded titles the possibilities for increasing the immersiveness of games is massive.

Speaking of being drawn into entertainment, like the Geforce 7 series of products the 8800 series features Nvida’s PureVideo HD technology which is responsible for providing exceptional video playback. When ATI first launched Avivo they had a clear lead in video quality when compared to the equivalent Nvidia part, since then Nvidia have been hard at work enhancing video quality and last time we checked they scored about 115 (out of 130) in the HQV benchmark compared to ATI’s 123. With the launch of the 8800 series Nvidia are reporting a score of 128points with the expectation that they will achieve 130 in the near future.

Like many recent products the Geforce 8 is a capable processor of Windows Media Video content and Mpeg-2. In addition the product also fully supports accelerated decoding of H.264, WMV-HD and Mpeg-2 HD formats. Future formats are also fully supported through the support in all 8800 series products of HDCP which will allow playback of HD-DVD and Blue-Ray discs when connected to a HDCP enabled display. Using the TV-outputs available on the 8800GTX 1080p support is available provided the connected display supports this high end feature and screens connected by DVI (Dual link) can be set up to 2560x1600.

So with the above explained you should have a fair idea of what the 8800 series is all about. For those who are interested in more in-depth information on DirectX 10, Nvidia have supplied a useful PDF which goes into great detail about the benefits and features of DirectX 10. For the less technically minded out there, a simple overview is that DirectX 10 was designed to provide everyone with a faster and better looking games and the Geforce 8800 series was designed to take full advantage of the individual aspects of DirectX 10. Read the PDF here.

Let’s take a look at the cards themselves.