Here's my problem, when I look around QUICKLY, it lags and you can see things in the background trying to load. I have a lot of mods, and many of them are retextures. I do get good FPS @1080p, 30-60 outside, and 60+ when inside. I'm not sure what to lower or what. Thanks in advance.

Well, quality comes at a cost...

Try lowering your view distance, as I think that lowering ingame resolution or texture quality is out of the question for you -and for me to be honest...

What should I lower specifically? There's a few things that I can lower to change the view distance quality.

Why not experiment?

I turned down distance detail to High and it still does it, but the lag is shortened.

Just don't expect it to entirely go away.

not knowing anything about your system ..all anyone can do is guess...I know a lot of tweaks for Nvidia..but dont know ATI

Others may know tweaks for ATI...

You really should not be seeing OVER 60 FPS either ..one of the Best tweaks i found for my Nvidia is capping the FPS to 59 while my Monitor is doing 60 HZ this gives me smooth fluid FPS constantly. I have 1 GB vram and using the DLC with a bunch of Texture mods also...

So...Nvidia or ATI?? that is the Question...

Try turning AA down first