FCP slowing down after some use

[Michael Alberts]

We’ve had similar problems for quite some time. Going back to FCP 3 or 4 we’ve noticed that render times can be improved with a restart. We’re now on FCP 6 and the problem still exists.
After several hours of use the render times increase greatly. For example a DVCPro 50 timeline will require 10 minutes of rendering, which I know, based on the material is way too long. After restarting FCP the same render will take less than a minute. There appears to be a memory leak issue with FCP that has existed for quite some time. That was one of the first things we tested after upgrading to FCP 6 (FCS2). No improvement.
One short term remedy is to add more RAM. We’ve found that more RAM allows you to work longer before the problem becomes noticable. Other than restarting FCP several times during the day we haven’t found a solution.

Michael Alberts
Ambidextrous Productions, Inc.
http://www.ambidextrous.net

[Anders Haavie]

Extremely annoying. Somebody must fix this now.

[Neil Ryan]

It was mentioned recently (I think by Walter) that FCP only uses 2gb of RAM. And I also think that this is mentioned in the online manual.

Confirmation anyone?

[Bill Wilson]

I am just a FCP user and not familiar with the FCP code itself. However, I think the problem is, in fact, a memory leak. A “memory leak” happens when an application begins executing and starts reserving chunks of memory from the free memory pool. The applictaion keeps this memory reserved until it finishes, at which time it should release the reserved memory back into the free memory pool. If the application code does not cleanly release this reserved memory back into the free memory pool, it remains in the reserved memory pool indefinately. Thus, it appears to the system and all applications running on it that the amount of physical memory diminishes over time, hence the phrase “memory leak”. The only way to release this memory back into the free memory pool is to reboot the system.

I notice in the activity monitor that the “blue” memory slice (inactive memory) continues to grow the longer FCP is executing as the “green” slice (free memory) continues to shrink. The memory in the blue slice is “inactive” but is not available for use. Heavier renders requires FCP to reserve more memory. The next time a render is required, FCP reserves yet more memory from the free pool. After quitting FCP, the activity monitor still shows a very large blue slice (i.e. this memory is not released back into the free memory pool).

The symptoms described by some FCP users, along with the output from the activity monitor is certainly consistant with the notion of a memory leak.

As far as I know, there is nothing we as users can do to manage this other than periodic reboots. As mentioned in the post above, you can delay the symptoms by adding more memory, but the problem still exists and will eventually catch up with you.

As a side note, I also seem to notice that as the memory leak situation progresses on my MacPro, I begin to see unexpected results in render output. If I delete render files and reboot, all render outputs are as expected. Whether this is a symptom of the memory leak issue, or something else, I don’t know.

Bill Wilson
SunDolphin Productions
Birmingham, Alabama