NVIDIA GeForce 256 Preview (Page 8/10)
Posted: October 11, 1999
Written by: Dan "Tweak Monkey" Kennedy
AGP 4X with Fast Writes
Although AGP 4X with Fast Writes is fully supported by the AGP 2.0 specifications, NVIDIA is the only graphics chip company that takes advantage of the technology, with the GeForce 256 GPU. Fast Writes improves performance on all operations from the CPU to the graphics chip, including:
AGP bandwidth wasn't much of a problem with the TNT2. However, the GeForce 256 will transfer up to five times the number of triangles so it will use up to five times the bandwidth. Fast Writes allow the data to go straight from the CPU to the GeForce 256, bypassing system memory. Although system memory is very fast, it's not fast enough to transfer up to 900 MB/sec with ease.
Below are a couple diagrams to help you further understand AGP 4X with Fast Writes.
- 2D operations
- Writing data to the frame buffer or sending data to the graphics chip
- Loading textures with Direct3D into local memory
- Writing push buffers to graphics local memory
This diagram shows how processing through normal AGP 4X works. As you can see, all memory is sent through the chipset and system RAM. This increases latency between the CPU and graphics card.
This diagram shows how processing works with the GeForce 256. With Fast Writes, the data is sent directly from the CPU to the GPU, saving resources and increasing performance significantly.
For most readers this is probably the least interesting section. After all, the 2D on your system is already very impressive and you don't need anything more, right? In case you do, here is what the GeForce 256 offers in the way of 2D:
The addition of a 256-bit 2D rendering pipeline as opposed to 128-bit means this should deliver incredible 2D performance with high refresh rates (don't forget the 350 MHz RAMDAC) at high resolutions and 32-bit color.
If your monitor supports it, this chip can manage 75 Hz at 2048x1536. The 2D will probably be the best to date due to the powerful pipeline, speedy RAMDAC, and AGP 4X with Fast Writes in combination. If you're a 2D enthusiast, NVIDIA has you covered. It's amazing what you can do with 23 million transistors, put in the right places.
- 256-bit 2D rendering pipeline
- 4 pixels per clock on all scaled and indexed image operations
- 1 GB/s CPU-to-GPU memory via AGP 4X with Fast Writes
Curious about HDTV yet?