The GIGABYTE Robust Graphics Booster (R.G.B) feature boosts 3D graphics performance on all DirectX8 and DirectX9 applications. Found on GIGABYTE 925X/915 family series based motherboards, GIGABYTE's R.G.B. optimized graphics cards pump GPU and VGA memory performance to the max. All is needed is a few simple BIOS settings, and no need to install additional software.
Yes, leave it on auto.