Andy got us some new numbers. The tests he tried to run most recently included GeForce 6200, Radeon 7000, a Matrox G550 (PCIe), and a Matrox G450 (PCI). The reason for the last two tests was to compare the effect of PCI vs. a faster bus on two very similar GPUs. Unfortunately the Matrox cards and/or drivers are too primitive to run Quake, so that's out.
Here are his results. The quoted figures are the 640x480 numbers, while the new (slower) figures are for 1280x1024.
GeForce 6200 AGP 256MB: quake3: 1346 frames, 7.0 seconds, 192.8 fps glxgears: 1360.8 fps
For 1280x1024, the GeForce drops down to: 1346 frames, 23.7 seconds, 56.9 fps
Sapphire Atlantis 7000 PCI 64MB DDR: quake3: 1346 frames, 43.4 seconds, 31 fps glxgears: 343.584 fps
For 1280x1024, the 7000 drops down to: 1346 frames, 137.7 seconds, 9.8 fps I'm going to offer up an assumption for us. I'm going to assume that Quake tries to show us the same image, regardless of the resolution. To do that, it would paint the same scene, using the same number of triangles. So when you go to a higher resolution, the same number of commands is sent to the GPU, but each command results in drawing more pixels. This assumption is probably wrong, but it's probably close enough to the truth that we can use it as a rule of thumb. Going based on this math, 1280x1024 has 4.27 times as many pixels as 640x480, so the higher res should have a framerate that is 1/4.27 of the lower res. The GeForce (on AGP) dropped in framerate by a factor of 3.3, which is in the right ballpark from the prediction. The Radeon (on PCI) dropped by a factor of 3.1, which is still in the right ballbark, unfortunately. This means that either PCI is fast enough to keep the Radeon busy, even at 640x480, or my hypothesis is wrong. Anyhow, given this incredibly limited amount of information, I'm going to throw out an initial projection that OGD1, with the OGA1 GPU, will have a framerate of somewhere between 20 and 30 FPS on Quake III at 1280x1024. The 20 comes from the fact that the low-end projection for OGA performance has twice the pixel throughput as the Radeon. The 30 comes from the fact that OGD1 has 3 times the available memory bandwidth (a pixel often requires more than one memory access). If we can prove that PCI is the bottleneck here, I'll have to reduce those numbers. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
