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Lightspeed Memory Architecture II Tech Brief
NVIDIA's LMA II delivers advanced memory bus bandwidth optimizations for the best graphics performance and quality. Get a behind-the-scenes look at LMA II technologies in this technical brief (165KB PDF).

Technical Brief: Quadro4 Lightspeed Memory Architecture II
The attached technical brief describes the key features of NVIDIA's Lighstpeed Memory Architecture II, and explains how they relate to professional applications and how they provide significant benefits to the workstation user (167KB PDF).

 Lightspeed Memory Architecture II

These days PC users run demanding 3D applications, sometimes simultaneously, and expect stellar graphics performance without a slowdown. The increasing complexity of multimedia applications and games, with features such as multitexturing and depth complexity that achieve rich image detail and greater scene realism, only multiplies the impact on a system’s memory bandwidth. Unfortunately, a GPU’s memory bandwidth can easily get bogged down as it is inundated with these high-bandwidth demands and multiple, continuous tasks.

Now, with the GeForce4 family of GPUs, NVIDIA introduces Lightspeed Memory Architecture (LMA) II, whose patent-pending technologies alleviate memory bandwidth bottlenecks, providing superior graphics performance and speed.

LMA II implements a number of new technologies to improve the efficiency with which a GPU renders pixels, including:

  • A crossbar-based memory controller: Ensures that every aspect of the memory system is balanced and that all memory requests by the graphics processor are handled properly. Under complex loads, LMA II’s memory crossbar architecture delivers 2-4 times the memory bandwidth of other standard architectures.
  • A Quad Cache memory caching subsystem: High-speed access buffers that store small amounts of data and operate at tremendously high bandwidth, ensuring that data is queued and ready to be written to the memory. These caches are individually optimized for the specific information they deal with, resulting in almost instantaneous retrieval of key data.
  • Lossless Z-buffer compression:Reduces Z-buffer traffic—one of the largest consumers of memory bandwidth in a graphics subsystem—by a factor of four, without any reduction in image quality or precision.
  • A visibility subsystem:Determines whether or a not a pixel will be visible in a scene. If it determines a pixel will not be visible, the pixel is not rendered, saving valuable frame buffer bandwidth.
  • Fast Z-clear technology:Minimizes the time it takes to clear the old data in the Z-buffer, boosting frame rates up to 10% without compromising image quality.
  • Auto pre-charge:Warns the memory device of areas of the memory likely to be used in the very near future, allowing the GPU to spend less time waiting for memory and more time rendering pixels.

All of the technologies utilized by LMA II combine to provide a tremendous leap in graphics performance. These technological advances pave the way for increasingly dynamic and visually rich real-time 3D graphics experiences. By improving the efficiency of communication between the host and graphics, content developers can continue to increase the geometric richness and visual complexity of their scenes to new levels. This provides end users with the most realistic, life-like images, environments and effects, without compromising performance.