I have a texture bug with the green grass model, I do not have any mods on right now ( Except for Dark UI / Immersive Interface ) so I do not know what is causing this.
Here's a picture of the grass:
It only effects this grass model, all the other models look normal.
I've also tried grass mods like "Shorter Grass" and "LowPolyGrass", none of them seem to work.
Here's another picture since the first one you can not see the bug very well:
Oh wow... I'm incredibly dumb, I had the nVidia control panel for Elderscrolls: Oblivion set to High Performance, I turned it to High Quality and now it's fixed.
Thanks for everyone who helped, I'll done this thread now.