Purpose
Most computer monitors use an "RGB" subpixel layout, so most computer software (including Windows itself) optimizes its text rendering to look good on this kind of display. However this kind of optimization starts to become undesirable in many situations, where it causes color fringing to appear around text.
Changing font rendering settings in Windows
Method 1: ClearType Tuner
Use the ClearType tuner: Windows > Settings > search: Cleartype