Rockstar really do hate PC users. All their responses to people asking about RDR for PC was "if it looks like it'll rake in more $ for us, we'll port it". Personally, I think GTA4 PC is better than LA: Noire PC. At least in their current states.
I hadn't really noticed the lag (the resolution letterbox was taking up the full extent of my blind rage against the game

) until others pointed it out

I know the PS3 and Xbox 360 are optimised for gaming and solely made for it, but the PS3 has 256MB RAM and 256MB of intelligent video RAM (if I remember correctly). Speaking as a PS3 owner who has played LA Noire quite a lot on it, why does that get to perform better than my PC that has 6GB RAM, a hexacore processor, and 1.5GB of video RAM?? Yes, there were visual issues with LA Noire and intermittent crashing on the PS3, but it was still a lot more fluid than on PC