FCPX bottleneck question

Discussion in 'Digital Video' started by pertusis1, Jul 12, 2014.

  1. pertusis1 macrumors 6502

    Jul 25, 2010
    I am going to apologize ahead of time for the fact that some of my ignorance will likely spill over into this post, but I'm not sure where to look next for information about my problem. From searching the forums, it sounds like I am not the only one with a FCPX workflow bottleneck question, but I can't find the answer to my question, so here goes.

    I am an amateur video editor, but I have been fortunate enough to cobble together what should be a pretty decent video editing machine over the last 2 years. My needs are not complex. I have about 50 hours of family videos (everything from Hi-8 to AVCHD) to try to archive. I found that FCPX was the most friendly with AVCHD files, so I am importing my files to FCPX, arranging an hour at a time of video, and exporting it to DVD, BlueRay, and Quicktime.

    My setup:

    MP 5,1 12 core 2.4 GHz, 48 GB RAM, MacVidCards 7970 video card, and most recently, a XP941 SSD.

    Here's my problem, and how I tried to solve it. Perhaps someone could suggest a smarter approach. I started with a stock MP 5,1 12 core with 12 GB memory and a 5770. When I used FCPX, I noticed that the 12 GB of memory maxed out. Thinking this must be bottleneck, I bought 48 GB of ram. Having done this, I then realized that OSX often uses all available RAM, and the new measure of RAM usage is 'pressure'. Needless to say, it did not improve my speed much, though I did feel better.

    The next clever observation I made was that while processing the videos, my CPUs never rose above 50% of 1/2 of the threads. Out of 24 threads, only 12 of them seemed active, and they were running at 50%. I heard that FCPX uses AMD video cards really well, so I got a 7970 card. This did help a bit, but I noticed that my internal hard drive (7,200 rpm) seemed to be I/O full speed, and I thought it may be a limiting factor. At this point, my real goal was to be able to run my 12-core at full speed :roll eyes:

    As such, I got a XP941 SSD, which is screaming fast by the numbers, but oddly did not change my FCPX rendering times.

    So here's my question. Does anyone know of an objective way of determining where workflow bottlenecks are occurring? I can't figure out why rendering is taking 60 minutes for a 60 minute 1080 video to convert it into a DVD? Is this normal? How can I make it go faster? I have a lot of videos to go through, and time is precious. I have read some people talk about 'scratch disks', but don't know much about this. Also, I was hoping a screaming fast SSD would limit the need for a scratch disk.

    P.S. - for what it's worth, before I got my MP, I tried this on a 2.6 GHz Mac mini with 16 GB ram. Rendering took it about 24-hours with the fan screaming the whole time. Obviously Geekbench scores aren't everything :mad:
  2. sevoneone macrumors 6502

    May 16, 2010
    Are you running the most up to date versions of Final Cut and Compressor? (FCPX 10.1.2 and Compressor 4.1.2) The 10.1.2 update has brought some very big performance gains for me on a quad core system with 16GB of ram and an nvidia 650ti card. I run my system off an SSD, but all my media is on spinning drives.

    Are you using Compressor to encode MPEG2 for DVD? If so, have you gone into Compressor > Preferences... 'Advanced' and checked the box for 'Enable Additional Compressor Instances?' After the 4.1.2 update I noticed that this had been turned off and greyed out on my machine. I had to use the Reset Queue... button and then the Repair Compressor option to be able to check the box again.

    I don't think there is a single person out there that has nailed down all the possible FCPX performance vectors. LOL. As I'm sure you have seen, it baffles many. What I have noticed is that the return for having more CPU cores seems to drop off between 4 and 8 (physical cores, HyperThreading doesn't make a big difference in my experience) and I can't tell the difference between an 8 and 12 core system that otherwise have the same RAM and video card.

    What people have found out is that FCP likes RAM and it likes GPU. How much RAM impacts performance depends on how complex your projects are.

    GPU is the big one. Ditching my original 8800GT and getting a 650ti has had the biggest impact on FCPX for me over any other upgrade, including my move to SSD.

    I don't recall where I saw this, but I do remember someone testing multi GPU setups in older MacPros to see how if you could get any gains from the optimizations for the new MacPro in FCP 10.1. He had two systems, one on an AMD GPU and one running an nVidia 650ti like mine. He installed a matching card in each machine and saw his rendering times nearly cut in half.
  3. pertusis1 thread starter macrumors 6502

    Jul 25, 2010
    Thanks for the response, even if only to confirm my feeling that many other folks have the bottleneck blues.

    I am running FCPX 10.1.2. I don't own compressor. Does this improve rendering workflow? I didn't figure it would be helpful if I could select the output that I wanted (DVD, BluRay or H.264) with FCPX. I notice that they advertise distributing work over more cores (or computers). Would this distribute the work over 12 cores better?

    I'm surprised that FCPX doesn't fully use the processor available to it. I thought it was supposed to be optimized for multicore use more than almost any other program. Furthermore, people seem to have 'render farms' to render their video faster, which led me to believe that more cores was better with FCPX. I must be missing something...

    Your observation about the video card is interesting. Perhaps it's not using the CPU because it is depending almost entirely on the GPU. I think my next test will be to time a render with my 7970, then switch it out for the 5770 and re-time the render.

    After writing my post above, my wife came by and read it and said, "why don't you just get a book and properly learn how to use FCPX?" doh!
  4. RCAFBrat macrumors 6502

    Jul 10, 2013
    Montreal, QC
    I just re-read your original post and noticed you didn't actually describe your workflow; perhaps this would be a good place to start? I understand that you think rendering can go faster based on activity monitor stats, but it may be that looking at your workflow will be more informative.

    For example, this works well for my son (late 2012 21.5 inch iMac with i7 CPU, 16GB RAM and 1TB HDD):

    (1) Import video, mostly 1080p shot with Canon T2i
    (2) Background render ProRes files immediately or while editing
    (3) Export finished project to ProRes (ie create a master)
    (4) Compress the master to Quicktime movie using Handbrake

    Step (3) doesn't seem to max out his computer, presumably since the HDD is the bottleneck however since there is no compression going on, it is pretty quick. Handbrake is a beast and maxes out the CPU, and I would have to say it is very fast. This workflow is a lot faster than having FCPX create compressed files for distribution.

    Food for thought!

  5. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    Compressing HD at 1080 to SD on DVDs in real time is not bad at all The DVD uses mpeg compression and if you can compress one hour ov content in one hour that is very good.

    I don't quite understand what you are doing. You are not editing just transcoding files from older formats to newer formats? If so then it seems you could queue this up and let it run while you go to work and at night while sleeping.

    It you were actually editing and the user interface was lagging that would be bad but beinbg slow while you don't have to wait?

    What software are you using? Apple just released a new version of Compressor. I've not had a need to use it yet.

    (BTW, you do know that storing 1080 content on DVD looses a lot of video quality.)
  6. Small White Car macrumors G4

    Small White Car

    Aug 29, 2006
    Washington DC
    2 things:

    FCX may be "friendly" to them but they still suck. You really should transcode them to Pro-Res when importing. (What Final Cut calls "optimized" media.) You can do it after the fact by right-click the files and selecting "Transcode Media."

    Yes, this takes time, but it'll work in the background. It also takes up drive space, which is bad, but trust me, everything will work so much better.

    When you're done working on something and you want to keep the project around for safety, select the project in the library and go to FILE > DELETE GENERATED EVENT FILES. That lets you erase all the optimized media to re-gain drive space while keeping the original AVCHD should you ever want to change the project in the future.

    This is absolutely your main problem.

    For video editing you need at least 2 drives. One for the OS and apps and the other for the Final Cut libraries to live on. Hopefully both of them will be fast, but at the very least the media drive needs to be fast.

    The problem is money. I could very quickly show you how to throw thousands of dollars at this problem.

    (Answer - Buy 2 of these babies: http://eshop.macsales.com/shop/SSD/PCIe/OWC/Mercury_Accelsior/RAID)

    And that's cool and all, but you're talking about home movies here. Maybe not worth that much cash.

    One step down is these guys for your hard drive bays:


    Maybe get a 240 GB boot SSD drive and a 480 GB SSD media drive and a 3 TB hard drive for everything else? That's more economical but it means you have to constantly move projects around as you finish them. 480 GB goes fast once you're using optimized media.

    (You also need to learn how to do stuff like move your iTunes library off your boot drive onto your large hard drive. 240 GB goes fast too.)

    Or, the cheapest method:

    Get a 240 GB SSD boot drive. Then get three 2 GB SATA hard drives. Use Apple's disk utility to create a software RAID across them. Now you have hard drives that are getting closer to SSD speeds AND it's 6 TB of space! This is cool!

    This is also dangerous. Now a single drive failure takes ALL of your data with it. If you're going to do this (and I do this myself) you need to have a ROCK SOLID backup plan that happens automatically every night. You are trading safety for speed.

    That's not ideal, but it's a good choice unless you want to spend thousands of dollars on multiple SSDs.

    - - - - - - - -

    Lots of options here. Feel free to run more questions by us. Every path you choose brings up yet more choices.
  7. pertusis1 thread starter macrumors 6502

    Jul 25, 2010
    Once again, thank you all for the helpful posts. I am leaving for a 2 week vacation, but when I return, I shall try a few of your suggestions.

    Briefly, my workflow does involve 'optimizing' the AVCHD video on import. I don't even notice this taking place in the background. For what it's worth, I have absolutely no lag when working within FCPX. The only editing I really do right now is inserting date and title labels at various parts of the video to identify locations, etc. Because of this editing, I don't know whether I could just batch a lot of jobs, then let it run. I'm not using a bunch of filters, etc. yet.

    My boot drive is really fast, but perhaps when I need is a set of media drives. I actually have several 3.5" spinning HDs kicking around that I'm not using, and could potentially set up a raid 0+1 in my internal bays, which would be faster, redundant, and relatively cheap (I think I would have to buy one additional HDD).

    I am not using Handbrake or Compressor for export. When I get back, i'm going to try one of these.

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