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To: fyodor_ who wrote (22705)	12/17/2000 4:41:51 PM
From: Steve Porter	Read Replies (1) \| Respond to of 275872

fyodor... AFAIK the xBox will also support driving a monitor, and/or HDTV. Bandwidth issue become important with anti-aliasing/games featuring many 'overdraw' type effects (where you go into the frame buffer and render 2d effects onto the 3d image, or even 3d effects onto the 3d image). These 'overdraw' type effects are going to become increasingly popular. I will dig and find out what exactly is going on, but I know nVidia is having problems getting more performance from their parts.. the nv20 is going to be 3-4 months late... Steve

To: fyodor_ who wrote (22705)	12/17/2000 8:20:21 PM
From: combjelly	Read Replies (1) \| Respond to of 275872

RE: XBox bandwidth. Well, they are delivering up to 5.4 GBytes per second to the GPU, I don't think memory bandwidth is a problem. Have you seen this "DR. Dobbs" article? ddj.com

To: fyodor_ who wrote (22705)	12/18/2000 9:33:15 AM
From: pgerassi	Read Replies (1) \| Respond to of 275872

Dear Fyodor: NTSC is interlaced and has a resolution of 640x480 (square pixels). The video boards in PCs actually sample at a higher rate of 720x480 from NTSC for better conversions after processing. With some newer TVs going to DTV and HDTV, the resolution will increase up to 1920x1080i (interlaced) or 1280x720p (progressively scanned (like most computer monitors but with 16:9 aspect ration)). Because the newer games seem to like high polygon counts, memory bandwidth becomes a problem for CPU load, I/O load, the video in load, the T&L load and the GPU load. The last is increased by overdraw by as much as 6x or more. While a 32 bit color 24 bit z buffer with an 8 bit stencil at 1920x1080 is a 16MB frame, displaying 30fps needs a 1 x bandwidth of at least 480MB/sec without counting texturing. Texturing adds about 320MB/sec and then a 4x overdraw factor (typical in newer games) make for a requirement of 3.2GB/sec for the GPU alone. Add 1.06GB/sec for the CPU and 360MB/sec for the T&L unit, you reach 4.62GB/sec. With requirements like this, even dual channel DDR starts to gasp. Reducing overdraw to 2x would allow for Dual PC1600 to satisfy top end requirements. Yes, the Gigapixel technology would help greatly. Just the experimental HSR in the 1.04.01a 3dfx drivers which, although buggy, allows a Voodoo 5500 to easily beat a GeForce 2 Ultra 500 at 1600x1200 4x FSAA (75fps vs 25fps). Pete