Some programs can be more usable if you choose GDI Scaling for them ('System Enhanced' display appcompat), a feature in newer versions of Windows 10.
This can distort text and bitmap graphics, producing blurring and pixilation. Most applications run in legacy mode, so everything gets scaled up through appcompat shims. In other words it trades away screen real estate for readability by 'magnifying' everything. The idea was to let you use the monitor's native resolution (very important for LCDs) while still having large enough text for you to read it. When your monitor has a gratuitously high resolution Windows attempts to help you cope by choosing a high-DPI setting.
