Best Practices for Space Saving? 4GB of video turned to 200GB!

Hi Everyone,

I am finally up and running and editing in FCPX. I uploaded two videos into FCPX this evening. The original files were about 3GB for both videos. I imported, selected "leave files in place" since I have them on an external HDD I use for editing, and selected "Proxy Media, ProRes 50%." 

Within about 10 minutes, my project was almost 200GB in size after doing some simple sharpening, optical flow, and color grading with LUTs. I looked to see the render files and these were about 50GB in size and the optical flow file is almost 100GB in size. One of my clips is 50FPS and another is 30FPS, so I used the optical flow feature to blend the frames as I was getting dropped frames. My project si 30FPS.

I have a 1TB Samsung Extreme Pro harddrive that I edit from and a 2020 Macbook Pro with Intel i9, 32GB RAM.

What are best practices for space-saving but being able to edit a video and watch it back during the editing process smoothly? 

I deleted my render files and turned off background rendering and now when I watch the video in "Proxy Media" in FCPX I get choppy footage in the viewer on my 50FPS clip. Is this because it needs to render optical flow? Just wondering what settings and best practices you would all recommend. 

I want to be able to export my project at the end in the best quality possible.

Thanks so much!  

Yes. OF really does a number on drive space and that's the reason I don't bother with it until the end of the project. I'm confident in what the effect is capable of and don't need to see it in action while editing. 'Choppy' wouldn't bother me on playback, only on final edit and that's precisely when I trust it to do its magic, then l make it a point to manually purge any rendered / optimized files.

Thank you for your response and your help!

When I'm done with projects, or just simply every Friday, I run FCP Library Manager, delete all the render and cache files for everything, and generated files for libraries I'm not currently working on. If you go back to a library you deleted the generated files for, it will remake them.