FCP Proxy footage causes dropped frames, but Optimized/Original does not.

Upgraded the external HD from 40-50Mbps throughput rotational platter ot 700+Mbps SSD. It's faster, but will have to see if it solves the problem.

Thanks. Gonna try moving to an SSD to hold the media while editing and see if that helps.

I converted it from Mac OS Journaled to APFS.

Details of original media: Just stock iPhone SE 2020 4K 30fps footage downloaded as .mov files onto the mac (except for a couple slo mo shots which are HD 240fps). Typical video is 3840x2160 resolution, 23Mbit/s, HEVC video format, MPEG-4 AAC 44.1kHz audio format, 8 bit depth, 16:9 aspect ratio, ranging from 7 seconds to 130 minutes.

The external hard drive holding my media is:

  disk9 - WD My Passport 2627 5.00 TB

  External USB 5 Gbit/s USB

    disk9s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

    disk9s2 [APFS Container] 5.00 TB

      disk10 [APFS Virtual drive] 5.00 TB (Shared by 1 volumes)

        disk10s1 - D****T (APFS) (4.41 TB used)

No indication in EtreCheck report of a slower-than-usual USB3 issue. Not going to post the entire report because most of it is irrelevant to the issue, or is a result of my forcing FCP to quit.

In Final Cut Pro, using optimized media does fine for playback but hangs up for awhile during editing. But proxy media drops frames during playback, and somehow doesn't seem to be much better for editing.

FCP library is stored on this same external hd as the external media.

Thanks for the suggestions.

I'll try removing Google Keystone. I need to retain Chrome itself because Chrome Remote Desktop is the primary way I access my M1 Mac mini. I operate it remotely from a high end Chromebook. For doing my final edits where I need to edit the audio and sync it to the video, I turn on my tv (HDMI out from Mac mini) and use a bluetooth keyboard/mouse combo. But even a huge 4k tv leaves the GUI text and details too small to see from across the room. The house is too small to put in a desktop setup or dedicated monitor, and I hate the neck strain of sitting at desks anyway. A laptop on the lap is the best way for me to work.

What other agents are known to break FCP?

Here's more detail into what is happening: FCP will run fine for a few minutes. All I'm doing is renaming clips according to their numerical order in the script, so that I can rearrange them after renaming (not all clips are shot in their script order). Then all of a sudden, FCP will start beachballing, and in Activity Monitor I will see FCP start to consume maybe around 112% CPU (even though CPU load graph is quite low with 82% idle), while simultaneously consuming ever-increasing chunks of memory. I have FCP background task monitor open, and it shows no activity. I have 16GB of memory, and it will start at 2GB and in chunks about 1GB more, work its way up to 8+GB. Memory used will go up to a bit over 12GB. No memory swap is occurring. FCP will sit like that for 3 to 5 minutes, then all of a sudden will go back to normal, consuming 2GB of the 16GB memory, and 0.7% of CPU.

The result is the same whether FCP is running on HDD or SSD.

I had deleted Chrome for awhile but later reinstalled it since I use it for Chrome Remote Desktop (Apple wants $80 for its less robust remote desktop solution that won't run on my Chromebook anyway).

With Chrome installed, when FCP goes through these episodes, Chrome processes are not consuming any significant resources.

This last episode, I noticed that Time Machine Backup had fired up in the background and was clicking away on a HDD external hard drive, and I thought maybe it was locking FCP out of its library file, but when I told Time Machine to skip this backup, it still took some time for FCP to recover. I hate how Time Machine Backup does that. It always was messing with iMovie this way, causing iMovie to hang up and crash. But there is no setting on Time Machine to pause backups for a few hours. You have to manually disable it, and then you'll forget to manually re-enable it for a couple weeks, putting your work in a non-backed-up status. I want Time Machine to run at nighttime, but there is no way to tell Time Machine to perform its tasks at night. You can only select once per hour, once per day, etc.

I guess I'm not following the logic here. Are system resources really being swamped when FCP is the only thing that is not responding, and when FCP is the only thing going momentarily crazy using system memory and greater CPU, while everything else during the episode is completely responsive (Finder, Activity Monitor, Safari, System Settings, Time Machine, whatever...)?