By default, Optimized/Original is selected for your media playback settings. Set the viewer to Proxy Preferred instead of original camera media. In the upper-right corner of the viewer, click the View dropdown menu, locate the MEDIA heading, and select Proxy Preferred. FCP will automatically switch your project to view proxy media.
When importing media from Frame.io, the original (full resolution and original codec) and lowest available resolution by default (around 360p) will appear in the Background Task panel before becoming available in FCP. The original camera media will be much larger than the proxy.
NOTE: Open Background Tasks temporarily pause the original file import until the proxy file has been completed. Now, the media is available on your timeline while the original continues to download in the background.
When you’re ready to export your project for sharing or review, you’ll almost always want to switch back to Optimized/Original media in the viewer by clicking the View dropdown menu and selecting Optimized/Original under the Media heading.