10.0.4 performance much worse for me...

I have same issue, is very heavy on CPU, and choppy playback even if before in 10.0.3 was okay. One issue I found is that is always rendering something in the background, even if deselected in preferences. How I make a small change in the time line, it starts rendering again. This is no good.

Sorry to hear about your troubles. Not much help, but for me it is just the opposite: had lots of beach balls yesterday, running smoothly now on 10.0.4. It may be hard to figure out the reason, but it serves to show that there is hope.

Exact same issue here. I'm using OS 10.7.3 on a brand new iMac 27" with plenty of RAM (16GB) and 2GBs on the graphics card. Internal SSD running apps and a 1 TB internal drive for media. Everything was running perfectly fine with 10.0.3 using original media working with 24p files converted to Prores 422 and using the optimized media setting. Suddenly, after the update to 10.0.4 there is horrible stutter and dropped frames all over the place. Completely unworkable. Had to go back to using proxy media on a silly little 3 camera project.

I certainly hope Apple takes a serious look at this issue in a prompt manner, or provides a way of easily reverting back to a previous version. This is completely unacceptable. Because of glitches and inaccurate syncing problems, that is exactly why I went ahead and did the upgrade, because .0.4 was advertising improvement with the syncing functions, but now....it's like a step backwards with this lousy playback performance. What gives?

It seems some of the systems out there actually improve their performance with 10.0.4, but my experience is exactly the opposite! This completely has me stopped in my tracks, because using the proxy media which looks like crap is not an option as I can't make good color correction decisions. Doesn't Apple vet these upgrades on all of their systems?! I also don't buy the idea of having to do so many workarounds. I have way over 30% hard drive capacity left, and there is no reason why this upgrade should become in reality a DOWNGRADE! I want to see a 10.0.5 up by the weekend addresssing this issue. Or is Apple bloating the code and playing the "let's obsolete the hardware" game before their next iMac refresh. Really ticked off about this! At the very least, keep a library of past versions available so that users can easily roll back, if they run into a problem!! Sheesh!

You should let apple know through feedback. If it is code specific to your system likely you will have to wait till 0.5.

But I'm guessing it could be a conflict with another program or plugin or a matter of cleaning up your system like repairing disk permissions.

0.4 had the oppiste effect on my tower performance and I use two screens with an ATI 4870.

Thanks Wild Giles!

I did exactly that. No word yet. I also repaired permissions, but that did nothing to improve the playback performance. I do not use any plugins, only Pluraleyes, a standalone app for syncing as the syncronize multiclips functionality is not reliable or accurate enough for my needs. Very strange. I'm hoping they discover the solution quickly.

One other trick you might try: In your project, select all, copy everything, go the project library, create a new project, and then paste in your previous timeline. Sometime projects get corrupted and this can solve the problem.

Knock wood, I had the opposite experience. Performance/snapppiness picked up across the board with 10.0.4. Runs much better. I am on 10.7.3--maybe that is the difference?

Also, where are your events and projects? On 10.0.3 I found a performance boost when I parked my project files on my internal system drive (although I know that many frown on that).

I'll try that, but things were fast and very smooth in 10.0.3 and I was already on 10.7.3 before I downloaded FCPX. I have a dual drive configuration, so all apps are on the SSD bootdrive, and all events and projects are located on the internal HD. No problems whatsoever in 10.0.3, but I discovered yet another problem yesterday. Events are not following their projects correctly. If I click on an event in the event browser it remains as the active event even when I switch into different projects. Maybe this is a normal behavior, but I find it wildly confusing and non-intuitive. Each project should show its unique set of event files. Could be operator error, but this also seems to have been corrupted somehow, or needs a look by Apple.

Lot of landmines exploding here. I don't think they are vetting the releases thoroughly enough.

Actually, FCPX shows you EVERY event and EVERY project located on every drive that is connected to your system. The good news is that you could pull shots from a variety of events if you needed to.

But it can get cluttered and confusing. That is why a must have utility is Event Manager X. It's only $5 but allows you to "hide" the events and projects you are not presently working on.

BTW, having a ton of events and projects "open" in FCPX may slog your performance, which is another great use to use this utility, which you can find here:

http://assistedediting.intelligentassistance.com/EventManagerX/

I wouldn't think of using FCPX without this app.

Of course I understand that the Libraries are showing all of the events and projects. That was clear from the beginning and evident with the new structural architecture of the app. With versions before 10.0.4, however, you could toggle between projects, and the event browser would change to show the related events for that particular project. Now it seems to be broken and the Event browser is not updating this information.

Also you are not reading the orignal poster nor my post carefully enough. EVERYTHING WAS FINE in 10.0.3. No performance related problems with the same number of events and projects at all. The poor performance STARTED as a direct result of the upgrade to 10.0.04.

System is working fine, upgrade, system slows down. The upgrade is the correlation here. Not any other element of the configuration.

Have you tried creating a new user account and logging into that account to eleiminate the system/caches/prefgerences as a factor?

I did that. Of course, it is problematic to test the same project this way, because I would have to rebuild all of the multicam clips and syncing all over again. The new user account does not allow the opening up of existing projects. Playing of a few individual files worked fine with the new account, but I'm not convinced the problem is preference related. I went back to the orignal admin account and copied the timeline into a new project, and for the first 10 seconds of playback it was fine again, but I noticed it was re-rendering the entire project. As soon as it was completely rendered, playback went back to the same abymsal choppy and stuttery behavior.

Can you describe the media in the project, describe the timeline, any stabilization or rolling shutter, retime, or stills used?

Also, not sure why your projects would be un-available to a new user account if you moved them to a media drive first.

The source media are AVCHD and MOV files from three different cameras: a Panasonic GH2, a Canon t2i, and a Sony nex-5n. No stills or any other formats incorporated. All 1920x1080p 24p. I did not do any retiming or extra processing on these files, neither was any stabilzation or rolling shutter processing added. They were, however, created as a multicam clip using Cingular Software's Pluraleyes, as mentioned, which takes the xml info does its syncing and spits it back neatly into a FCPX timeline. But I then created a fresh project after the syncing with Pluraleyes, opened up the multicam in the Angle Editor did color matching and quite a few color corrections, and then went out again into the timeline to perform some simple edits. There are only 5 titles used in the timeline. Very simple.

My iMac27" is a dual drive configuration. When I went into the new user account, I noticed that I could only import to the SSD bootdrive from the other internal 1TB drive which houses all of the orignal files, and the Final Cut Event and Project folders, et al. I could not find a way to import old Projects into the fresh Final Cut Pro X app. It was only showing the internal SSD bootdrive as the only media drive available. Strange. It could be operator error, as I don't go back and forth between other user accounts very often. But when I drilled down into the event folders via Finder, I could only see original media associated with some newly imported camera files. The Plural eyes MC files, other synced multicam files, and well as the original media for the edited project were not showing up. There is probably a good reason for this, that I'm simply not aware of.

But the crux of the problem remains: 10.0.3 - exellent performance, 10.0.4 - only barely useable with proxy media.