This is a temporary fix until ATI can sort there drivers. For most of you having issues with your FPS with ati cards the issue is the shadows. The options allowed ingame do not let you turn off shadows. ATI is notorious for having shadow issues. So the only work around is to disable them from console.
In order to turn on ingame tilde console goto your steam library and find brink. Right click and choose properties. The on the General tab select SET LAUNCH OPTIONS and add this.
+com_allowconsole 1
Start up brink and open the console with tilde key, left of number 1 key on the top of your keyboard.
Type this
r_shadows 0
Enjoy
Edited its r_shadows 0
