Outside areas in Vanguard my machines run pretty dang good without much problem, it might skip here or there. When it comes to anything at all that is inside, IE Houses,Caves,Tunnels, my graphics start to behave badly. It's hard to explain but like every other wall disappears then reappears over and over again randomly. It gives me the sense that something isnt working right when the inside zones render. Anyways does anyone have an idea on what maybe is the culprit? I have it narrowed down to two thoughts, its either the fact I only have 1 gig of ddr2 ram in my system or that I am used a Nvidia 6 Series card. Any thoughts?

Hmmm, are you using the most recent NVidia drivers? Apparently they're still in beta phase and are somewhat wonky. I would recommend probably going back a version, install that then do a fresh install of the latest DirectX 9 afterwards.

If this doesn't fix it, let me know.

Try turning on/off hardware occlusion in your gfx settings (in vg), thats a buggy option that does that once in a while.

and if you have AA running it will do that as well.