I'm not sure whether I'd been playing for way too long in one sitting, but only in Red Rock Canyon does my framerate drop to about .75 FPS for some reason. It took me about 10 minutes to walk through the passage from the encampment to the Red Rock Drug Lab just to have it discovered. When I eventually am able to fast travel out to, say Chance's Map, the load takes FOREVER but I get there and the game runs a bit worse than normal. I have an 80GB Metal Gear Solid 4 bundle system(software backcompat). Any suggestions?

If it's any consolation it drops on the 360 too!

I think all the foliage, Kahns etc overload the Gamebryo engine at Red Rock Canyon.

I'm currently playing it on a 40GB PS3, and have to say the load times in general are longer than on the 360, and I have had one or two that took a good few minutes. I don't know if it's an issue with how the PS3 partitions its memory?

When the frame rate drops a bit in other areas that should be fine, have you tried saving then reloading the save?