FCP Runs Slow on iMac Pro

If you have lots of projects or project snapshots it can cause slow behavior when navigating between libraries. In each library, select the Projects smart collection in the top folder, and see how many projects and snapshots you have. Please report the total number for each library.

There is a separate issue if you have imported "bare" AVCHD clips using "leave files in place." Those usually have an .MTS file extension. Those can cause extremely high I/O rates which is noticeable when changing libraries or events, if the viewer is in "filmstrip" mode. Even if just a few of those clips are imported to a library that mostly contains other types of media, the AVCHD clips can "poison" the I/O capability of the entire library. That media type should be imported using "copy to library" or, ideally, rewrapped externally before import using EditReady.

Please investigate these areas and report back. If none of these apply, the next time you have a 60-sec beachball, please take a Spindump using Activity Monitor. Procedure:

• Run Activity Monitor
• Select the FCP process in Activity Monitor
• In FCP reproduce the beachball behavior
• While it's in a beachball state, in Activity Monitor, do View>Run Spindump, or else use CTRL+OPT+CMD+S keys (all at once).
• After the Spindump is generated, in the upper right corner, click the "Save" button and save it as a .txt file.
• Upload the text file somewhere I can see it. That text file will be about 8 megabytes, likely too large for an attachment on this forum.

Tom -- Do you have any other suggestions for how I can get this file? I tried posting a link to a WeTransfer upload folder, but I was warned against that.

I have now examined the spindump extensively, and believe the problem might be the large number of synchronous I/O operations being performed to inspect assets and check proxy availability whenever switching between original/proxy media. The high thread count and GCD queue utilization indicates FCP is processing a complex task with many assets, maybe thousands of clips.

How many of your media files in all libraries on this machine have proxies? Are the proxies stored inside the library (the default) or did you define an external storage location (ie outside the library)? If so, what drive type are those on, and what drive type is the library itself on?

I have edited documentaries using a library containing 8,500 4k H.264 clips, all of which used proxies, and that was on an iMac Pro. It was a bit sluggish but I had no problems switching between proxies and regular media. The library was on the internal SSD and the media was on a 32TB OWC Thunderbolt 4-drive RAID-0 array. In this case I used the FCP Library Inspector to define a separate storage location for the proxies. I think I had those on another drive array.

Your Etrecheck report shows you have several kernel panics, the last of which was on 4-15-24. Do you remember the circumstances? Did the entire machine crash or spontaneously reboot?

[Edited by Moderator]

Thank you for giving plenty of information up front; it saves a lot of back and forth.

Right off the bat, the issue is surely with I/O, not the processor or memory, which are plenty fast enough.

If I/O is the bottleneck, a new Mac is not likely to help that much.

I will have a look at your report.

In the meantime, you may run Blackmagic Disk Speed Test on those external drives. What does it say?

There might be some indications in the spindump that threads are hung on URL-based media references, such as media on a network or cloud-based resource. Do you have any media or libraries on any network or cloud-based location?

Do you have iCloud Drive enabled in the Mac's System Settings? If Desktop & Documents Folders is enabled, any media you store on the Desktop or in the Documents folder is in iCloud.

You have many external drives connected.

Several of your drives, particularly rotating hard drives, are essentially full.

This causes them to slow down considerably.

If you can, try a test: disconnect your rotating hard drives, and open one big library from the external SSD.

Do you still see the same slowdown?

I can see that you have a lot of files, obviously requiring a lot of space.

I think this all depends on how much media you need to access for the same work.

If you can fit a production in, say, 4TB, or 8TB (as opposed to, say, 24TB), I'd do all the editing on an SSD, and

keep the big fat rotating hard drives for backup and archive.

You could get yourself one or two external SSD, or even a RAID.

You can even get a RAID box (e.g. from OWC, a company providing Mac peripherals for a long time) with empty drive bays, which will allow you to grow in time, and support either HD or SSD.

Using SSD, a RAID will probably not add much speed, if any, but will allow you to make a BIG SSD out of a few smaller ones.

FWIW, I would only edit from a rotating HD if I absolutely had to. SSD are so much better.

An FCP spindump is about 8 megabytes of text. That might be too big for an attachment, but the main thing we want to see is from the top of the spindump down to the bottom of the main thread -- the first thread listed. If the users could just use TextEdit (in plain text mode) to copy that to another file, it is only about 60-70 KB. It could be attached to a post.

But that is only one case. We really need a way to exchange troubleshooting files.

Just to set a benchmark here, I am running an iMac Pro with a very quiet Promise Pegasus3 R8, very fast, no issues. In fact, I'm surprised my M1 Pro Max MBP is not really much faster than the iMac Pro, except for exporting from FCPX, which is sort of kind of significantly faster, but not blazingly faster. 50% of my system drive is free space (it's only the system drive that needs the free space, secondary drives don't matter). So, there you go, I would think as stated this is an I/O issue.

Oh, I'll throw out there that too many external drives connected to a computer at one time can slow the whole system down a bit. Seen it over and over, lots and lots of small drives on one computer. Connect the one your using at that time, leave the others disconnected.

Yeah, the older and some smaller Promise RAIDs are a bit noisy when they get warm.

I have been over the TOA many times, but the listed items apparently are different from the actually applied items. I can't tell what is permitted and what's not. Is there some other list you could send me which would help navigate this?