MICROSOFT TALISMAN

The Microsoft Talisman project was developed over the last couple of years to help design a better rendering solution for games.

The Talisman reference spec calls for using 4 Mbytes of shared RDRAM, and two, 600 MHz, 8-bit Rambus channels. This configuration thus yields a potential throughput of 1.2 Gbyte/Sec. 

The SIGGRAPH ’96 paper states that a scene complexity of 20,000 to 30,000 rendered polygons, or higher, can be supported using the Talisman architecture which is comparable, says Microsoft, to a 3D graphics workstation capable of executing 1.5 to 2 million polygons per second. And the Talisman cost? Microsoft quotes a bill of materials cost of $200 to $300.

A few companies have indicated they are working on 3D capable cards. PCI cards today are fine for work processing and spreadsheets but they lack any 3D capability.

Memory bandwidth, and system latency. Microsoft’s numbers state that the data from a 75Hz, 640 x 480 x 8 frame buffer need 23 MB/sec to scoot across. At the other extreme, a 1024 x 768 x 24 frame buffer for the same 75 Hz update requires 169 MB/sec. Memory bandwidth has been a limiting factor that has noted for years.

While the work with Talisman is interesting the reality is that a lot more work is needed in hardware design to solve some of the issues needed to handle 3D graphics.

The new first person shooters that are wildly popular are going to pressure the design of the central processor as well as lead to new ideas for 3D graphics.

The ATI Rage XL PCI VGA Card 8MB (as above) is a basic card for CRT displays. The goal of Talisman was to improve the 3D capability as Intel was developing the new AGP slot. PCI cards are popular as they are able to handle 640×480, 800×600 and 1024×768 resolutions in true color (24-bit/32-bit).

The Proview monitor with its 1280×1024 resolution can handle all standard resolutions easily.

Intel said the new AGP slot will separate the video card from the main PCI bus so that system performance will improve. Intel designed the AGP slot to be extensible so that as their designs improve the bandwidth can be bumped up.