Trident XP4 Preview - A Cheap GeForce4?

Although the majority of the transistor savings come from Trident's unique implementation of their four rendering pipelines, other things such as having no fixed function T&L help reduce transistor count as well; fixed function requests are internally converted to vertex shaders by the XP4.

The lower transistor count coupled with the 0.13-micron manufacturing process give the XP4 very low power consumption of between 3 - 4W on average. While this is still a bit higher than we'd like to see for mobile use, it's clear that Trident has the notebook market in mind as an application for the XP4.

The XP4 has long been rumored to be a tile-based rendering solution like STMicro's Kyro II and as intriguing as deferred rendering technologies are, you won't find any such technology in the XP4. Instead, the XP4 is a conventional immediate-mode renderer like the GeForce4 or Radeon 9700 but with a tile-based rasterization engine. All this means is that the XP4 uses a tile-based algorithm for storing pixels in its frame buffer; so instead of writing lines of pixel data to the frame buffer the XP4 writes the data in blocks/tiles. The XP4's tile-based rasterizer is much like Intel's 845G graphics core in this respect, and the main reason behind it is to optimize for the XP4's internal caches. The end result is improved memory bandwidth efficiency, which helps tremendously considering that the XP4 has no real occlusion culling technology.

Trident supports supersampling AA and anisotropic filtering with the XP4 but it's not clear how their unique architecture is impacted by enabling higher order filtering techniques or antialiasing.

The XP4 has a single 420MHz RAMDAC but it supports multiple displays through the use of a digital LCD or TV-out alongside a single analog monitor.