You can automatically generate smaller versions of your videos for faster editing in DaVinci Resolve, sometimes called "proxy files", using the "optimized media" option. In File > Project Settings you can define how they will be generated (resolution, encoding, etc.) and then you right-click on the videos and select "Generate optimized media". Then, if you have the "Use Optimized Media If Available" option checked in the Playback menu, you'll be using these "proxy" videos when editing, which can make things dramatically faster.