Clean sweep. Install the 10.8s which were one of my past favs. Everything runs fine still.
Log file from Quake 3:
GL_VENDOR: ATI Technologies Inc.
GL_RENDERER: ATI Radeon HD 5800 Series
GL_VERSION: 4.0.10151 Compatibility Profile Context
GL_EXTENSIONS: GL_ARB_multitexture GL_EXT_texture_env_add GL_EXT_compiled_vertex_array GL_S3_s3tc
GL_MAX_TEXTURE_SIZE: 16384
GL_MAX_ACTIVE_TEXTURES_ARB: 8
Log file from Quake 3:
GL_VENDOR: ATI Technologies Inc.
GL_RENDERER: ATI Radeon HD 5800 Series
GL_VERSION: 4.0.10151 Compatibility Profile Context
GL_EXTENSIONS: GL_ARB_multitexture GL_EXT_texture_env_add GL_EXT_compiled_vertex_array GL_S3_s3tc
GL_MAX_TEXTURE_SIZE: 16384
GL_MAX_ACTIVE_TEXTURES_ARB: 8