stress test Mac Pro FCPX

The brief was simple, push the new Mac Pro and FCPX to the limit. Never mind 4k or 8K, we went large on everything until things broke. Alex Gollner and Peter Wiggins perform the ultimate stress test.

We had the pleasure of welcoming Alex Gollner to the FCP.co offices, he had come here on a mission. What started as an idea at the recent BVE exhibition, ended up being a full blown test to see exactly where the limits of the Mac Pro and FCPX began.

A few notes before we start. The footage that we used was the ProRes demo material from the new Blackmagic 4K Cinema Camera. We also left FCPX set to Better Quality. (Actually we forgot abut the setting until about halfway through the tests!) All Libraries were local and the big media was stored locally as well to benefit from the fast SSD storage. 

Here's our trusty Mac Pro configuration.

fcpdotco mac pro


So first question: What is the largest number of connected clips you can have stacked up in FCPX?

We would like to say that this is a comparison to FCP7, where the maximum amount of video tracks was 99, but as FCPX doesn't have tracks, we chose to occupy the 'lanes' with connected clips.

Alex started to add 4K connected clips one on top of each other at 1 frame intervals. He got up to 100 quite quickly.

(Click for larger image)

FCPX Mac Pro stress test


The Mac Pro handled this with ease, then we went to 200 connected clips, again no problem. Feeling confident, we decided to cut and paste. 

Pasting 200 connected clips to make a total of 400 took a second, pasting those 400 again took two and a half and pasting 800 took four seconds with the dreaded beach ball appearing momentarily. We did turn the Timeline Index off as we noticed a considerable lag when things got large with it enabled.

Time to go bigger. We stopped at 1600 connected clips, but proved that FCPX doesn't really have a lane limit. Your main problem here will be seeing all the clips in the GUI, especially as the clip on the top lane will fall 1599 places if you razor blade the end and there's no clips below it!

FCPX Mac Pro stress test 2


Then we had to see if it would play. To give the Mac Pro a chance, we reduced the number of clips in lanes down to 1000.


Of course it played! Well the Mac Pro played the first 50 frames before looking like it was dropping frames, but 50 'layers' of 4K playing back for a couple of seconds is pretty impressive.

We also timed the Mac Pro taking 1'42" to render 100 clips stacked on top of each other that were set to 50% opacity in the Inspector. That's impressive too.

So having worked out that for the majority of users, FCPX will supply more than enough lanes for editing (or tracks if you really want to call them that) we took a look at how large the resolution could go.

Alex made a five second 16K self contained movie from Motion. The project consisted of 1 pixel lines with a fisheye filer, it took 29 seconds to export a ProRes 422 file. FCPX then made a project to those dimensions when the clip was dropped on to the timeline.

FCPX Mac Pro stress test 3


So a 15360 x 8640 clip, that's 132,710,400 pixels per frame, or 64 times the data rate of HD. Would FCPX play that? No, with that data rate you would need a very fast RAID, but it did try. When somebody develops a RAID that can push 7,488 MB/s into a Mac Pro, we will try again! 

So time for a different approach, how wide can you make an FCPX project?

With all the talk about 4K, 8K or even 16K, we thought we would really supersize things. We created a 500,000 pixel wide by 1080 pixels high project.

500 pixel wide project


So why would you want an odd sized project? For a start, FCPX could be the ideal way to build media for digital signage. Rather that take the traditional path of constructing things in After Effects and having to render to see the finished result, FCPX would be able to play back video and graphical elements from Motion in real time.


As you can see, FCPX had no problems playing the timeline, but the scaling and the export failure leads us to think that not everything is happy. Maybe it is taxing the graphic cards too much.


How many clips can you have in an Audition?

A test that is more likely to be encountered by editors, just how many instances can you squeeze into an Audition? We had only got up to the low thirties before and as we can see editors building updatable graphical projects made up from Auditions, this was an interesting one.

audition test fcpx


We were slightly disappointed when we hit 128, FCPX just wouldn't take any more. The control of the clips in the audition also becomes a bit unwieldy as although you can just about detect the end stops when cycling through the clips, you lose the star of the original clip in that row of dots.


And finally, what is the longest FCPX timeline you can build?

We save the best for last. We had a few ideas before we set off that the timeline limit would be something sensible like 24 hours, or a round binary equivalent in frames. Can you have a round binary number?

How wrong we were!

Alex started to build up a timeline made from a two hour clip. Going over 24 hours was easy, as was 48 hours. Once a week long timeline was built, he added markers at day intervals, then kept on copy and pasting.

Followed by more copying and pasting. 

We got bored when a 279 day timeline had been built! That's 602,635,302 frames or 24,105,412 seconds or 401,756 minutes or 6,696 hours.

579 day timeline


Are we crazy? No, we went one step further and doubled it up to make a 558 day timeline!

Would it play? 


Of course it would, although it took a few seconds to stop dropping frames. This really blew our minds as the thought of setting off a timeline to play, then coming back a year later to find it only just over half way through is incredible!


We pushed FCPX and the Mac Pro to silly limits, of course nobody will make a year long or a 500,000 pixel wide timeline, but it's good to know the combination will go that far.

It seems that the real limitation is a hardware one, yes FCPX will do 16K, but you have to have the storage bandwidth to supply the huge number of pixels per second. When creating that huge timeline, we used the same clip over and over. Making the same timeline from different shorter clips wouldn't be as easy as we think very large numbers of clips within FCPX will slow the machine down.

Apple have however, built a combination that will be good for nearly all different media sized projects within the foreseeable future. The Mac Pro and FCPX handle 4K like SD, so 8K should be fine. 

We will leave the last words to Alex, who we owe a big thank you for making the trip and spending the time with us.

Stressing Final Cut on the new Mac Pro tells us that Apple's programmers haven't set most of the application's limits based on the needs of editors. Instead of writing code that assumes editors would never need to (or want to) work with 16k footage, connect hundreds of layers or create year long timelines, developers have in effect said "Hey, as long as you can find hardware fast enough... Go for it!"



Written by
Top BloggerThought Leader

I am the Editor-in-Chief of FCP.co and have run the website since its inception ten years ago.

I have also worked as a broadcast and corporate editor for over 30 years, starting on one inch tape, working through many formats, right up to today's NLEs.

Under the name Idustrial Revolution, I have written and sold plugins for Final Cut Pro for 13 years.

I was made a Freeman of Lichfield through The Worshipful Company of Smiths (established 1601). Though I haven't yet tried to herd a flock of sheep through the city centre!

Current Editing

great house giveaway 2020

2020 has been busy, the beginning of the year was finishing off a new property series (cut on FCP) for Channel 4 called The Great House Giveaway. I also designed and built the majority of the graphics as Motion templates. It has been a great success and the shows grabbed more viewers in the 4pm weekday slot than any previous strand. It has been recommissioned by C4 for 60 episodes, including prime-time versions and five themed programmes. The shows have also been nominated for a 2021 BAFTA.

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Although both were postponed to later in the year, I worked again on ITV's coverage of the Tour de France and La Vuelta. 2020 was my 25th year of editing the TdF and my 20th year as lead editor. The Tour was the first broadcast show to adopt FCPX working for multiple editors on shared storage.


BBC snooker the crucible

BBC's Snooker has played a big part in my life, I've been editing tournament coverage since 1997. I'm proud to be part of a very creative team that has pioneered many new ideas and workflows that are now industry standard in sports' production. This is currently an Adobe Premiere edit.

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Covid cancelled some of the regular corporate events that I edit such as trade shows & events. I was lucky however to edit, from home, on projects for Amazon Kindle, Amazon Black Friday, Mastercard and very proud to have helped local charitable trust Kendall & Wall secure lottery funding.

As for software, my weapon of choice is Final Cut Pro and Motion, but I also have a good knowledge and broadcast credits with Adobe Premiere Pro, MOGRT design and Photoshop.

Plugin Design & Development

I'm the creative force behind Idustrial Revolution, one of the oldest Final Cut Pro plugin developers. It hosts a range of commercial and free plugins on the site. One free plugin was downloaded over a thousand times within 24 hours of release.

I also take on custom work, whether it is adapting an existing plugin for a special use or designing new plugins for clients from scratch. Having a good knowledge of editing allows me to build-in flexibility and more importantly, usability.


Now in its 10th year and 4th redesign, running FCP.co has given me knowledge on how to run a large CMS- you are currently reading my bio from the database! Although it sounds corny, I am pretty well up on social media trends & techniques, especially in the video sector. The recent Covid restrictions has enabled live FCP.co shows online. This involves managing a Zoom Webinar through Restream.io to YouTube and Facebook. 

The Future

I'm always open to new ideas and opportunities, so please get in touch at editor (at) fcp.co. I've judged film competitions, presented workflow techniques to international audiences and come up with ideas for TV shows and software programs!


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