FCP X: Avoid Lion Slowdowns

Posted on by Larry

Recently, I’ve gotten reports of sluggish FCP X behavior in Lion. William Hohauser sent this in, which I found so helpful, I wanted to share it with you.

While the newest update to FCPX has improved the program and eliminated several bugs, at least for me, it has introduced a new issue that was not there before. This is on my 2009 8-core MacPro with an ATI Radeon HD 5870 1024 MB video card and 16gb of system RAM.

Since the introduction of Lion I have had Mail and Safari enabled to be full screen apps where I can use a four finger swipe to access. Since the new update I noticed that FCPX would slow down especially during exports when I would swipe to the Mail program or Safari. In fact the whole computer would visually freeze up at times although the export was still going. Switching between applications was slow and could take a while before the next program actually appeared on the screen.

Activity Monitor did not show anything out of the ordinary so I downloaded the program atMonitor to monitor the video card. What I saw was that full-screen apps can absorb up to 70% of the VRAM even though you are not on the particular program. This was clearly conflicting with FCPX and slowing things down. Once I stopped using full-screen app function on the program, FCPX exports are back to normal and I still have both Mail and Safari open. In fact I just was exporting with FCPX and writing part of this while keeping an eye on the VRAM stats. With FCPX open and exporting the VRAM hovered around 70% used. With the export finished I quit FCPX and the VRAM dropped to 10% with Mail and Safari open. Before, with full screen apps activated, the VRAM stayed at 70% regardless of whether FCPX was open or not.

Larry replies: Thanks, William, for writing this up.

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6 Responses to FCP X: Avoid Lion Slowdowns

  1. frank suero says:

    WOW Larry, this is just amazing. I did the same test and on my 2009 Imac with only 512 of Video memory the porcentage jump to 79%. This is something that will help a lot. Now we are looking at everything on the oldest mac here at the home office.

    Thanks a lot for the great information

  2. Mari says:

    I have noticed, much to my annoyance, sluggishness whe using FCP X on lion. However, I’m not sure this explanation makes sense to me. As far as I know, full screen playback in FCP X is not in use until one intentionally toggles it on. Is William referring to removing this feature altogether from the program? Additionally, there is no Full-screen app function in FCP X as in other programs. I’m not sure how to not use the full-screen app function on the program… if that function isn’t available in the first place?

    • Larry Jordan says:


      FCP X has a “full-screen” mode in that it will remove the menu bar at the top, provided you are running OS X 10.7 or later and select this option from the Window menu.

      It also can display video full screen, regardless of the operating system version you are using, by typing: Shift+Command+F


  3. Graham Davies says:

    I am finding that the new FCPX is very slow when rendering or burning DVD’s. The previous version FCP 10.0.4. is about four times faster. Is there anything that can be done to speed up the new version? I have tried using both programmes today and the older version is much faster.

    • Larry Jordan says:


      I agree. I am getting LOTS of reports of problems burning DVDs with the latest version of FCP X.

      First, be sure to use the “Send Apple Feeback” form inside Final Cut Pro to tell Apple.

      Second, export your project as File > Share > Master file and burn it to a DVD using other software, such as Roxio Toast.

      Third, read this article: http://www.larryjordan.biz/fcp-x-export-problems/


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