I have a Radeon HD5870 and I am running Steam on Ubuntu 12.04 LTS, trying to play Serious Sam 3 BFE. When I run the game on Linux I see very poor performance and quality.
For instance, I am now on the level called "The Silent Riddler". First the frame rate is very low, I have the game set to High on CPU, and GPU MEMORY, and for GPU it is set to High, then I change the settings to disable all anti-aliasing and ambient occlusion. With these settings on Linux I get 15 - 25 frames per second, and the quality of the rendering is terrible. With these settings the detail in the foliage and the shadows under the trees constantly flicker in and out of existence, and when I go into the one closed room on the level my flash light turns on and my frame rate drops below 5 frames per second.
With Windows 7 on the same machine I can put the settings at High on CPU, Ultra on GPU, and High on GPU memory (no custom changes) and I get a beautifully rendered environment with 30 - 60 frames per second (that's 30 when I'm surrounded by enemies and unloading clips of ammo and 60 when there are no enemies around).
So I have a couple of questions. Can I force Windows to use OpenGL rendering so I am doing a more "apples to apples" comparison? If so, how? Is there some way to improve the quality of the rendering and the frame rate on Linux? What could be causing the disparity between the two operating systems?
Is there any other information I can provide that would be useful to the AMD Linux driver developers?