Why is my raptor slowing oblivion?

It seems that the game lags whenever i go to a new area. Those buildings and plants just pops out after the lag. Why does it do that? I have defraged my drive and closed the as much programs as im allowed. I dont think its the ac3 codec as i tried to disable it of oblivion and i still get the lags (although when i close the game down, my task bar seems to have a gazillion of them -but they're gone when i point my mouse over it).

and also, why does the textures edges glows? when i talk to someone on the dark (or go to the 3rd person view), all i can see is the tracing around them. Its more brutal on cities with have lots of edges on it, it seems that its so sharp and shiny. I use ATT if that matters.

Oblivion settings : 16X10, everything max, hdr+2xaa

anyone please help