You understand what their trying to do? If turning down something on YOUR settings helps with FPS, they can look into that feature in the game and find any issues that would cause low fps. It's the same everywhere, people using various GFX cards with various drivers and various overlays. All of this can cause unintended effects with certain gameplay systems. Make sure you do what they've asked too - Supply your specs and dxDiag so they can work out if it's a specific driver or something else.