Running an intel 20" imac, bone stock - that means 2ghz core duo with a radeon mobility x1600. I'm running the latest signed catalyst mobility drivers straight from ATI. I've also tried the drivers that apple provides with the boot camp 1.1 driver disc as well as the 6.2 based omega drivers - all of them have the same issue.
When I shoot a mutagen container and enter the green cloud, the framerate drops to one to two seconds per frame. I did not typo that. When the effect drops, everything returns to normal speed. Running in dx7 mode works, but I'd like to think the radeon x1600 is a dx9 part.
Has anyone seen this issue before? I know it's unrelated, but Oblivion has the same issues with oblivion gates and whatnot whenever a refraction shader is in use - same slowdown happens at the start of HL2:E1 with the vortigaunts. Again, refraction shader completely kills my framerate.