Enjoy your 1080P@60HZ Resolution,Please Note:
1.Supports resolution up to 1080P@60Hz,but we recommend you to make sure your monitor/tv could supply corresponding output.
2. If the resolution of your laptop is higher than the external monitor.
For windows: Windows Menu--> Setting--> Display--> Advanced Display Settings, set your laptop's resolution same as or lower the resolution of external monitor.
For MacOS: Left-upper Apple icon-->System Preferences-->Displays-->Mirror displays. Then your VGA monitor would mirror your Mac. However here you have two choices. One is "Optimize For" your built-in Retina Display, the other is "Optimize For" your HDMI monitor. You can choose which one you like.