***AGP: Can Intel save PCs from grainy 3D?
By Rob Glidden
It a rare day when a new bus pulls into town, and some 400 systems
engineers came to kick the tires of the PC's new bus at Intel's AGP
conference (Santa Clara 5/30-31).
AGP, for Accelerated Graphics Port, is Intel's new bus standard to
bring "arcade quality 3D to the volume price-point PC" according to
Intel vp Mike Aymar. For this crowd, AGP is 3D's official coming
out as a technology that will drive PC hardware design.
Initial support seemed strong. Given Intel's success with PCI, its
motherboard share and recently announced 3D chip deal with
Lockheed Martin, other motherboard and chip makers seemed eager
to implement AGP quickly (scheduled to ship in volume 2H 97).
Intel bills AGP as a special purpose supplement to the PCI bus,
specifically to handle 3D texture bandwidth. AGP is superset of a
66MHz PCI bus, implemented as a special purpose point-to-point (1
AGP to 1 CPU per system) connection between the CPU and
graphics chip.
So what is AGP for? Intel pitched that the main purpose is to offload
3D textures from graphics memory to systems memory. The pitch is
that 2 megs of graphics memory has too little room for the amount
3D games are demanding (a 2 meg board at 640*480*16 resolution
with z buffer has little or no room left for textures).
But there were skeptics that AGP would be limited to special
purpose texture swapping. Microsoft's Jay Torborg made a
presentation that pointedly emphasized using AGP to eliminate the
geometry, rather than texture, bottleneck (vertex data of 50 bytes per
vertex puts a 3D ceiling on a 40MB/sec PCI system of 800K vertices
per sec).
Note that AGP will access only physical, not virtual memory, so will
not in itself solve the megatexture plans of some coming 3D games.
Contact: www.intel.com
Wave Issue 9601 6/23/96 Article 6-01