Why am I not able to turn on the Overdrive setting on my Acer monitor?
Overdrive is enabled by default when your Acer monitor is connected via DisplayPort with FreeSync enabled. This means you will not be able to change Overdrive settings within the monitors On-Screen Display (OSD) menu.
Note: Overdrive can be enabled or disabled if the monitor is connected via HDMI, since FreeSync is not supported via HDMI.