FCPX super laggy on a 8000$ 15' MBP?

Hi everyone!
I am having some issues with FCPX, it is not recent, but I am starting to be fed up with it. When I work on project videos on FCPX, it tends to get super laggy, not only on playback but also simply to move my timeline, or stuff like that. I am having a hard time to conceive it could come from the hardware, since I am working on a 2018 15-inch Macbook Pro with everything maxed out (i9, 32 Go Ram, Radeon Pro 460X and 4 TB SSD Nvme).
My footage comes from my iPhone 12 (Filmic Pro shot in 4k Extreme Movic quality) and a Go Pro Hero 8 Black, 4K 30 fps.
I really am having trouble figuring out why FCPX is getting so slow over time. I tried consolidating the library but no luck. I also heard working in "proxy" could help, and If I am correct it means having the FCPX library on the internal SSD, but working with all the footage and assets on an external SSD?
Thanks a lot for your help on the matter!

Hikenkami wrote:

..I am having some issues with FCPX, it is not recent, but I am starting to be fed up with it. When I work on project videos on FCPX, it tends to get super laggy, not only on playback but also simply to move my timeline, or stuff like that. I am having a hard time to conceive it could come from the hardware, since I am working on a 2018 15-inch Macbook Pro with everything maxed out (i9, 32 Go Ram, Radeon Pro 460X and 4 TB SSD Nvme).
My footage comes from my iPhone 12 (Filmic Pro shot in 4k Extreme Movic quality) and a Go Pro Hero 8 Black, 4K 30 fps. I really am having trouble figuring out why FCPX is getting so slow over time...

The material from an iPhone 12 or GoPro Hero 8 is typically 4k and 30 or 60 frames/sec, highly compressed and difficult to decode. The i9 CPU in your MacBook Pro has Intel's Quick Sync video accelerator but it can only handle certain codec variants. In general it doesn't work as well on 4k 10-bit or 10-bit 4:2:2 H264 or HEVC files. However there are many variants of those codecs, with some worse than others. In general GoPro material is among the slowest and most difficult to handle.

The easiest solution is create proxies. Here is a Larry Jordan article about that:  larryjordan.com/articles/final-cut-pro-x...oved-proxy-workflow/

Re "slower over time", that can happen if you add certain compute-intensive effects or plugins. You can examine that possibility by creating a duplicate of your project timeline, open that, select all timeline clips with CMD+A then remove all effects with Edit>Remove Effects. Then try the same edit operation and see if it becomes faster. If so repeat the above steps but remove Fx from 1/2 of the timeline, then the other 1/2, then 1/4, etc until you find the problem area and what effects are involved.

Bugs in certain plugins can create a memory leak situation where FCP memory consumption constantly increases. You can check FCP memory consumption in the MacOS Activity Monitor, memory tab. Also the memory pressure graph should be green, not yellow or red.

I recently had a situation where an audio plugin was causing the computer to “beachball” me every time I made a change on the timeline. It could be a plugin issue.

Also, as Joema mentioned, the HEVC codec used by iPhone (I don’t know what codec Filmic EXTREME is) is very hard to decode without the proper hardware. Same with GoPro footage in some cases. Select the footage in the browser and right-click, select “transcode” and choose either “Optimized” or “Proxy.” Note that if you select “Proxy” you will want to also change the viewer to Proxy mode, it doesn’t do it automatically. Select “Optimized” if you have lots of space. All these do is make copies of your media in ProRes (or Proxy now gives you the option of h264 if you are short on space). ProRes is very easy for your Mac to play back and is designed for smooth editing rather than tiny files.

Yes some people keep their master files on a separate disk (the files directly from the camera) and use the proxies stored in the library to edit. This is really beyond my ability to explain but you can look into it. The purpose of this method is to save space and edit with a lower quality (but easy to edit) copy of your footage and then when you re-connect your drive change the viewer back to the original media for your final export or finishing.