Editing with the New iMacs

Posted on by Larry

OK. I’m impressed!

Last November, the day they went on sale, I ordered a 27″ iMac to replace my main editing system. (Click here to read about the system I ordered.)

It arrived the end of December and, as these things tend to work out, as soon as I unpacked it, I needed to give it to our talented production assistant to do some web database work for the last two weeks. (First, its a tribute to the admiration I hold her in that she was even able to TOUCH this system and, second, I felt like she was using a Ferrari to ferry kids to and from school.)

Finally, she went back to school. Now it was my turn. While I haven’t done a ton of work with it – yet – I want to share what I’ve learned.


This thing is fast! It loads fast. It runs smoothly. It renders quickly. Export is faster than real-time.

The screen is clear and easy to read – even considering the small point sizes of much of the text. And it has speed to burn.


Here are the specs of the system I purchased. I was especially intrigued with how the Fusion drive would work. The Fusion drive combines the speed of a Solid State Drive (SSD) with the storage capacity of a standard hard disk (often called “spinning media”). I knew that I would be getting external storage, so I didn’t get the largest Fusion drive, as I didn’t see the benefit of the extra storage.

Also, I am not a fan of wireless keyboards or mice, especially for desktop systems. If something goes wrong with the system, you often need a wired keyboard or mouse to fix it. I found the wired keyboard and mouse worked great.

For this article, I edited a one-hour ProRes 422 project. Single-stream video, dual channel audio running at about 15 MB/sec. (This is about five times the data transfer of a single AVCHD video stream.)


To get started, I did a quick test. Launching FCP X on my 2010 MacPro 4,1 took 24 seconds. Launching FCP X on my new iMac took 4.3 seconds. 6 TIMES faster!


The Fusion Drive combines the high storage capacity of a traditional hard drive with the high performance of flash storage. With a Fusion Drive in your iMac, disk-intensive tasks in Final Cut Pro X, such as importing and optimizing media, are faster and more efficient.

A Fusion drive “learns” what files are used most often and moves them from the spinning hard drive to the SSD. This means that it delivers the best performance to the files you use the most often. (As a sidelight, with today’s technology, SSDs are significantly faster than spinning media, in fact, SSDs are slightly faster at reading (playing back) data than writing (recording).)

So what does this mean? Last week, I was at the Storage Visions conference in Las Vegas talking with a variety of storage and system developers trying to better understand SSDs.

NOTE: There is an inverse relationship between performance and speed. The faster a storage device is, the less data it holds for the same amount of money. 7200 RPM drives deliver data more slowly than a 15,000 RPM drive, but the 7200 RPM drive holds more data. SSDs are faster than spinning hard drives, but, for the same amount of money, spinning hard drives hold more data.

The Fusion drive does not cache files; that is, make a copy of the file from the hard drive and store it on the SSD. Instead, the file is stored either on the hard disk or on the SSD, but not both. Files you use the most are stored on the SSD to provide the fastest performance.

Using the Blackmagic Design Disk Speed Test, available in the Mac App Store, I measured the speed of the Fusion drive: 323.1 MB writing, and 411.3 reading. Whew! Truly fast!!

However, even though the Fusion drive is amazingly speedy, I don’t recommend it for storing your media. This is because you’ll get the best performance from this drive when you are accessing the same files over and over – such as the operating system and applications. Media files are generally played once, and they are done. Constantly playing different files, or rendering different portions of the timeline does not benefit from the speed an SSD can provide to the same extent.

SSD drives work the best when accessing the same files – like databases, or applications – or when working with lots of smaller files.

When editing video, a better option is to attach a Thunderbolt RAID as your media drive; which is what I did. I’m using the G-Technology G-RAID, which is a two-drive RAID 0.

When I measured the speed of the G-RAID, it was slower than the Fusion drive, but provided far more storage: 4 TB vs. 1 TB in the Fusion drive; the G-RAID has a maximum capacity of 8 TB.

NOTE: RAID 0 drives don’t provide any data redundancy. If you lose either drive, you lose all your data. For editors needing more storage or even faster performance, I recommend using one of the Promise Pegasus RAIDs, which provide RAID 5-level data redundancy. Here’s an article on RAID levels.

By way of comparison with other speed tests I’ve published, here is the speed of the G-RAID as measured by the AJA System Test utility, available from the AJA website, illustrating speed variations as the size of the file changes. Notice that the speeds average about 260 MB/second for both reads and writes.

NOTE: To save space, I rearranged the elements in this screen shot. The numbers, however, are untouched.


The Fusion drive automatically transfers files between the hard disk and the SSD. You don’t need to do anything, the operating system decides what to put where.

When working with very large files that exceed the free space on the SSD, you may experience stuttering playback with high-resolution video. (This is one of the main reasons I recommend using an external Thunderbolt drive for media storage.)

Thunderbolt RAIDs, depending upon how they are configured, can provide faster throughput and greater storage capacity than a Fusion drive. This is especially important for multicam work.


In addition to the Fusion drive, the other big speed boost in the iMac comes from an improved graphics card.

The CPU processes instructions one after the other – serially. The GPU processes multiple instructions at once – parallel. Parallel is always faster and ideally suited to a variety of video tasks.

All effects in Final Cut Pro X are Motion projects, so using effects in FCP X or Motion benefit from using the GPU. Exporting that requires transcoding (like converting ProRes into H.264 for web viewing) will be faster. Other operations such as color grading, Ken Burns Effects, and speed changes also benefit because they use the GPU for realtime playback and background rendering.

For my system, I only got 1 GB of video RAM (VRAM). I learned from Apple that more VRAM means faster rendering, exporting and better realtime performance.


While the CPU and RAM can’t be ignored, we already know how these work. My system has a Quad-core 3.4 GHz Intel i7 CPU and 16 GB of RAM. (The reason a 4-core CPU generates 8 bars in Activity Monitor is due to Hyper-Threading, which is worth a whole separate article.)

During normal editing operations, I was cruising along using 12-15% of total CPU cycles. This allows plenty of overhead when the editing gets more challenging – say with multicam work.

RAM usage, when running Final Cut Pro X editing a single stream of video, hovered around 2 GB. (The red pie slice indicates RAM used by the operating system. Yellow is RAM used by open applications. Blue is RAM assigned to an application, but not yet used. Green is unused RAM.)

NOTE: ProRes (which uses I-frame compression) uses less RAM than long-GOP video codecs like HDV, AVCHD or XDCAM EX.

This proves a point I’ve been making in my classes and webinars recently: virtually every Mac shipping today is fast enough to edit video; even 2K or 4K images. The real test is the graphics processing unit (GPU) and the speed of your storage system.


I got the 27″ iMac because I wanted the larger monitor size. It truly makes a difference when watching images. I can see a 720p image at 100% size and still have plenty of room for the Event Browser and Timeline.

I had a spare 24″ Apple monitor sitting around doing nothing, so I plugged it in. Works great. Now I can edit projects using one or two monitors.

This isn’t necessary, but it sure impresses clients!

NOTE: A two-monitor setup would be especially helpful if you are editing 1080p material, or larger, as you could display the Viewer to your largest monitor and view your image at 100% size. All my current work is shot for the web at 720p, so the extra monitor is nice, but not necessary. I principally use it to display the Event Browser.

Apple makes a point of highlighting the reduced reflections of the screen. I didn’t notice a big difference between the new monitor and my older 24″ monitor. Video looked great, text was totally readable and the reflections in the glass didn’t bother me because I made a point to position the screen to minimize reflections.


I did two quick Multicam tests. The first was a six-camera XDCAM-EX shoot and edited using the XDCAM EX video format natively. (You need to install the XDCAM drivers by downloading Sony’s XDCAM Transfer software – a 30 MB download.)

When editing multicam, be sure to set Preferences > Playback to Better Performance to avoid dropped frames. Also, I recommend checking all three dropped frame indicators to make sure you aren’t experiencing hard drive problems.

Six streams of XDCAM EX video took 12% of my CPU and 38 MB/second of data during playback. However, XDCAM EX uses MPEG-2 as its compression codec, and can become taxing on your system as the stream count rises. For example, when editing the XDCAM EX footage natively, I could easily edit six streams of video. However, I got a few dropped frame warnings when I quickly jumped around in the Timeline, or cut too quickly. The dropped frame warnings were not serious, but I wanted to see if I could eliminate them.

So, I did a second test by converting all six video streams to ProRes 422.

Now, FCP X was pulling more than 100 MB/sec from the G-RAID during the edit.

However, the CPU load was well less than 20% and FCP X used less than 3 GB of RAM.

When using ProRes 422, no matter how fast I cut, or how much I jumped around inside the Timeline, I did not get a single dropped frame error.

NOTE: This requires a Thunderbolt drive. FireWire speeds top out at 85 MB/second, which is not fast enough to edit more than four streams of ProRes 422 video. There is a serious performance benefit to optimizing media when editing multicam projects.

The performance of this iMac system makes me want to shoot a project with 10-12 cameras just to watch FCP X edit it.


Frankly, this 27″ iMac blows the doors off my MacPro. It edits single camera projects easily. Its ability to edit multicam projects is limited only by the speed of your storage – with the caveat that optimizing media into ProRes is strongly encouraged.

If you are looking for a system that can handle whatever video format you throw at it, I am VERY impressed with this new iMac.

As always, I look forward to hearing your comments.


90 Responses to Editing with the New iMacs

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  1. Aaron says:


    Thank you for your quick response and great info! I took a trip down to my local Apple store today as well, and picked their brains apart for about an hour. Came home and pulled the trigger on the i7, with the 1TB Fusion! I’m not sure if you mentioned somewhere in your research here or not, but I did find out from the rep at the store, that with the Fusion drive the exact amount of dedicated SSD is 128 Gigs.


  2. Andy says:

    Hey Larry I am about to pull the trigger on this machine but with a 3tB fusion, after market up grade to 32GB RAM (using AE nowadays and has become necessary), coming up from a late 2011 27″ 3.4 i7 2GB GPU and 32GB RAM, and my question remains in this, I host my referenced media on a 6GB thunderbolt, and my events folder is located on the same drive where optimized media is created. The project files are typically hosted on my native drive. Is this the best suggested workflow (or should I host my project files on the ThB drive as well?) considering the Fusion drive, and do you think I will see benefits here in FCPX/AE/Motion performance. Love to hear your feedback, My performance on my machine thus far has been amazing, but the machine is a work machine and I need this for my personal work flowing in asap.

    • Larry says:


      What you are doing is not “wrong,” but you will get your best performance from the Fusion drive when you access the same files over and over. So, the single Fusion drive won’t be much, if any, faster than your Thunderbolt drive when accessing a single file. And, if you have 2-drive Thunderbolt drive, the external drive will tend to be faster.

      So, your system will work. If it were me, I would put both Project and Event files on the external drive.

      In terms of After Effects, you can put your comps anywhere, because they are tiny. Do a test and see which is faster, putting your AE render files on the boot drive, or the external drive.

      Other than that, you have a very nice system.


  3. Andy says:

    Great thanks Larry!

  4. As FW is not included with the new iMac. What do you use to import from a device that has FW/800 or 400 to the iMac? I have to clear our physical space before I can pull the trigger on a new iMac per my DW!

  5. Bob says:

    I have the late 2012 iMac i7 with fusion drive. I’m starting to learn Adobe Premiere and am using the internal drive now for editing. What are the disadvantages of using the internal drive to edit, then move all project files off to a thunderbolt drive.

    Also I note that Thunderbolt speed on most drives only comes into its own with raid 0. What if I need the security of backup. Should I get to double drives – using Raid 10 – or is that overkill?

    • Larry says:

      Generally, an external RAID 0 Thunderbolt drive will be faster for media than an internal drive, even a Fusion drive, because SSD drives only hit their speed when you are accessing the same files over and over.

      RAID 5 drives are very slow coming to market due to extremely long test/evaluation/approval process from Intel and Apple. I’m hoping to see that approval process speed up later this year.


  6. dylan quirt says:


    I didn’t see that work around that you mentioned for the Premiere w/ the new imacs video card. I am wondering if thats the issue i am having with jerky playback in certain areas.

    I have a 27″ Imac 2.9 ghz w/ 8 gb RAM and the factory vid card – Running R3D media via USB 3 drive ( at 7200 rpms). I usually work in Avid with MXF – So the premiere word combined with the R3D native world is alittle new for me – Also this is a new CPU i bought, as I was advised that the factory model would be fine. Please let me know

    • Larry says:


      My first suspicion is the USB drive. USB 3 is not optimized for media files, especially R3D files. I would try a different drive first.

      Adobe CS6 is not accelerated for the new iMacs, only the MacBook Pros. I know that Adobe has announced GPU changes with their next release, but don’t know if this iMac is supported. Check Adobe’s website to find out more.


  7. dylan quirt says:

    Thanks for the Quick reply – I wasn’t aware that USB 3 wasn’t optimized for media files – Its advertised and being X faster then almost everything else out there – Having said all of that what would you recommend ? the drive has FW800 which i just tested – via the Thunderbolt converter – and its having some issues too ) or ESATA, which the CPU doesnt have – Do you think a direct thunderbolt connect will fix this issue – If so i would need another drive, which isnt the end of the world, i just want to make sure that i am certain before moving in that direction



    • Larry says:

      No, what I really suspect is that native R3D files can’t be played on a Mac that doesn’t have hardware GPU acceleration.

      Check with the Red site.


  8. dylan says:

    Larry, If i swapped out the 27″ iMac ( the slower version ) for the faster version, with the better Graphics card do you think that would fix my issue – I dont need to play back at full res, 1/4 is fine, but currently i cant ever do that. I could also throw in an additional 8 gb of RAM, after i swapped the CPU out – Obviously i want to avoid all of this if it doesnt correct the issue.

    • Larry says:


      R3D files are very difficult for most computers to play natively. Currently, the CS6 version of Premiere does not support the GPU on iMacs. I would wait for the next version, which Adobe announced at NAB, to ship before making any purchasing decisions. Once the new version is out, you can ask Adobe for their advice on the best Mac to play RED files on.


  9. Mona says:

    Hi Larry —

    Now that you’ve been using this machine for a few months, are you still as happy with it as you were when you first started?

    I’ve got a mid-2009 macbook pro that I’ve been using hooked up to my monitor as my every day machine, and I really feel like I need to relegate back to being my backup laptop again. I began to use this to replace my aging MacPro (mid-2006) that was finally beginning to show it’s age earlier this year and I decided to put into retirement. I’ve been trying to decide what my next step is — and while I know that intellectually I can go back to PC and buy a very powerful machine for the same $2K, I have been so happy with my macs that I am afraid to go back to PC and the problems that have surrounded them in the past.

    that being said – I am a graphic designer who does a lot of work with photoshop, but also does some motion graphics work within premiere/after effects. I am a creative cloud subscriber and plan on using the latest and greatest software tools when they come out in June. Will I be unhappy with the performance of an iMac if I max out the memory at 32 gigs? I know historically that once I invest in one of these machines, they last me a long time… and I’m hopeful this would be the case with the iMac also…

    • Larry says:


      So far, though I don’t edit feature films on this system, I am very pleased with it. For FCP X, it is excellent. For Premiere, be SURE to check Adobe’s website to see if the iMac you intend to buy is supported by Premiere.


  10. Sam says:

    I’m looking at doing a very similar imac setup to yours so thanks so much for the Blog Larry.
    Whilst I am an experienced editor I am hopeless when it comes to IT and have little mac experience. I have always had an IT person taking care of the machine for me so I only had to worry about the editing.
    I’m going to be setting up my own suite for the first time. My current debate is, do I buy from the local Apple reseller/service centre? They have good knowledge of edit systems. I like that I can pick up the phone for easy advice and that I can take the machine in when something goes wrong. The extra cost (which includes upgrading ram and testing) is $450AUD, equivalent to three hours of their work time – for me that’s quite a considerable amount, but in the long term might be worth it for the easy support.
    If I order on-line, I’m confident I could upgrade the ram myself, but I’m not sure what else to expect. Will my mac arrive ready to plug in and start editing or is there a bit of know how required, configuring drives etc?

    • Larry says:

      If you are truly “hopeless” at configuring a computer spend the extra money. The peace of mind will be worth it.

      However, adding RAM and installing software these days is not difficult. I have every confidence you can handle it.


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