Editing video on a previous generation Apple iMac

... when you're used to a MacPro and you're worried there may not ever be another one.
Scott Simmons
By Scott Simmons 12.16.12

As Apple’s big, expandable, workhorse towers - the Mac Pro - has been seemingly left withering on the vine the last couple of years and a lot of professional editors with it. Many of those editors have moved to a laptop or an iMac as their primary edit machines rather than purchase a new tower. I’ve been somewhat critical of an iMac as a primary edit machine but the inclusion of Thunderbolt is really one of those “game-changers” for the dedicated editor. A conversation with Apple around the time of NAB led to a loaner iMac (this was before the new super-thin iMac was introduced) as well as a Promise Pegasus RAID showing up on my doorstep for evaluation and testing. Apple is confident an iMac can make a great primary edit system. I’ll be the first to admit I was pleasantly surprised at the editing experience though it might not be perfect for everyone.

The iMac I was using

What were the specs on the iMac I was cutting on? The MacOS System Profile is great to see just that.

This was a fast machine (the fastest at the time) but it would require more RAM if was to be used as a primary editing machine.


This talk of editing primarily on an iMac has been renewed with the arrival of a brand new iMac right at the end of November. The specs look good and they are a marvel of engineering in that they are thinner than before. I finally saw one in person the other day and they really are a very sleek design. While all the work I did was on a previous generation iMac there’s already been a couple of articles published discussing the new iMacs and video editing: both here on PVC and elsewhere. If you read to the end of this article you'll also see more discussion on these new iMacs which is important since my testing was on a previous generation iMac with an entirely different GPU. And that GPU distinction is an important one.

These newest iMacs lack an optical drive so that means no DVD burning on board. This will be a consideration for many editors. I still burn DVDs, both data-DVDs for easy client deliverables as well as the occasional video DVD. For $79 you can add an Apple USB SuperDrive so that’s just something to be aware of. Lacie has one for $50. And there are external Blu-Ray options as well. 

What’s the biggest drawback of using an iMac vs. a Mac Pro as a primary post-production computer? Lack of expandability is the obvious one. You can add RAM and you can upgrade the internal hard drives but other than that what is in the case is what is in the case.

Then along came Thunderbolt.

Thunderbolt makes an iMac actually usable

That lack of expandability on an iMac means no PCI slots to install different types of expansion cards. But Thunderbolt solves a lot of that since you can think of Thunderbolt as a PCI bus that connects devices externally with cables. It’s not exactly the same as there are some bandwidth limitations that exist with current Thunderbolt speeds that don’t exist with PCI Express, which is the type of PCI bus in the current Mac Pros. (check out this article from Carey Dissmore about why he’s considering a move to PC as to some of those limitations). But the truth is many editors will never hit the wall of those Thunderbolt vs. PCIe limitations and that can make the iMac a good choice for the video editor.

If you have a lot of PCI cards that you need as part of your edit system then the choice has always been a MacPro (or a PC but this is a Mac article and I’m a Mac user). With Thunderbolt it’s now conceivable that those already paid for PCI cards could be dropped into an external Thunderbolt enclosure and still be usable. It has taken awhile for those enclosures to begin shipping so the best way to see what is shipping is to ask Google. Here’s what I found as of this writing:

I haven’t used one as of yet but I’ve seen a mostly favorable reports on this technology. More on that later.

It remains to be seen if the current Thunderbolt spec can efficiently handle one of the biggest reasons many post-pros need PCI slots: GPUs for NVIDIA’s CUDA technology. Currently it cannot. Many apps are accessing CUDA to do the heavy lifting (Adobe Premiere Pro and DaVinci Resolve are the most common) and Thunderbolt bandwidth can’t match what you can get out of a MacPro just yet.

But for many the GPU limitations won’t be an issue as they don’t need any CUDA anything. What helps to make the iMac very usable is that Thunderbolt is fast. Just take a look at these drive speed tests I took with the configuration I had:

Above are speed tests on the Promise Pegasus R6 from both the AJA and Blackmagic disk speed tools.


That’s fast. But the reality of many (maybe most) editors working in post-production today: You don’t need uncompressed HD. You work with 1920x1080 HD but the compressed HD codecs (DNxHD and ProRes) are so good you don’t have to have these kinds of speeds to get work down. I’ve even seen some people that are still using Firewire! But just because you’re only working with ProRes doesn’t mean you should skimp when it comes to your media drives. A RAID 5 configuration means there’s redundancy in case of a drive failure. That’s a perfect reason to invest in a proper RAID right there. These speeds also mean you’re much less likely to run into multicam playback issues when cutting many angles at once in something like the Final Cut Pro X Angle Viewer. You’ll also get more responsive applications like Photoshop or After Effects when their disk caches are located on a fast RAID.

But more than anything else a fast RAID means one less thing to worry about. RAID 5 (or RAID 6) means less worry about a crash, speed means no worry about dropped frames or stuttering playback and a ton of space means you’re less likely to fill the damn thing up. What’s not to like about a big, fast RAID array?

Okay maybe the setup and maintenance of the thing is more difficult than a single firewire drive but most all professional RAIDs have some utility for setup and monitoring of the unit. The Promise Pegasus is no exception.

The Promise RAID includes its own dedicated utility for setup and maintenance on the unit.


There are a number of different tools in the Pegasus RAID utility.


I’ve heard some mixed reviews on technical support from Promise as a whole but I know several people with Pegasus RAIDs and they are happy with their units. While I never got close to filling up these 12 TBs of storage the RAID performed flawlessly. You’ll get something similar from other drive manufacturers as well.

What’s missing

Let’s begin with what I perceive as the negatives of using an iMac as a primary editing station. I say I perceive as I’m looking at this as what would I do if I was purchasing a brand new Mac as my main editorial system today. For my money and for the way I work, what would be the limitations of an iMac for editing and what would be the overall positives as a primary edit station?

The first thing I noticed when I sat down to go to work on the iMac was the keyboard and the mouse. iMacs ship with Apple’s multi-touch Magic Mouse and I had tried one of those when they first shipped only to eBay it a few weeks later. I still find the multitouch-ness of the surface to be too distracting during normal editing tasks. Apple’s older Mighty Mouse which is my mouse of choice. The tactile feel of the Mighty Mouse’s scroll ball is much better for editing tasks and provides a nice border between left clicking and right clicking which is a must do for editing.

The place where I almost smashed the Magic Mouse into a pancake was when using the Autodesk Smoke Pre-release. There were times when touching the wrong place on the Magic Mouse would cause a part of the current Smoke window to scroll wildly off screen. That was quite maddening but a mouse is easy to replace and there are many choices so that wouldn’t keep me from an iMac as an editing workstation.

The default, wireless iMac keyboard would be another instant replacement. Besides the fact that it’s wireless (I’m not a big fan of wireless since they always seem to need a battery at the wrong time) it’s just too small for a keyboard that I would have to use all day, every day.

With a small keyboard the FCPX Command Editor (obviously) doesn’t show the keypad, F13 − 16 or the arrow and movement keys as an option. The extended keyboard is a must-have option when editing.


But the biggest thing it’s missing is a dedicated number keypad. I’ve mapped many NLE commands to the keypad keys so instantly there are a lot of buttons missing, including some vital function buttons. But equally important is the lack of a keypad means no very fast, very efficient timecode entry in the NLE. Be it specific time codes for assembling a paper edit or + and - numbers for navigating a timeline the keypad keyboard is a must. Add to that Avid Media Composer’s ability to remember a + or - timecode by repeatedly hitting the enter key and the keyboard is the second thing I’d replace after the mouse. Actually I’d replace them at the same time as they both need to go.

The keyboard and mouse issue is really a trivial one as you can add a better keyboard and mouse for no charge as an iMac option when buying in Apple’s online store. I’m not sure how that works at a physical Apple store. Small considerations overall but important ones when putting together an edit system that you’ll be sitting in front of for hours and hours each day.

The other big thing that is missing on an iMac (and big is a relative term depending on what you’re wanting an iMac to do) is an NVIDIA CUDA GPU. That was the case on the old iMacs but the new ones do have NVIDIA graphics. More on that in a minute.

What’s nice about editing with an iMac

Once I had the iMac up and running it did a great job of cutting just like any other editing computer, depending on the application I was working in. The iMac is fast and cranks through most editing tasks. The combination of an SSD boot drive along with a second internal drive as well as the external Pegasus RAID is unbeatable when it comes to speed. I dumped a lot of stuff on to the extra internal drive as a weigh station depending on what the task at hand and leave the RAID reserved mainly for media and renders. The newest iMacs offer what Apple calls a “fusion” drive so that’s another thing to consider if purchasing a new iMac. If I was buying the new one only as a mission critical edit machine I might skip the Fusion drive as its performance in an edit suite is a bit unknown. Wait it out until people have used it for a while. But if you’re a serious editor you always store your media on some type of dedicated media drive anyway.

Obviously Final Cut Pro X is a primary app for an iMac editor and the iMac runs it beautifully. Avid Media Composer is another application that didn’t seem to care if I was on my Mac Pro or an iMac, especially since it was a supported configuration. Most apps ran just fine on the iMac and many felt considerably faster overall since the iMac had a much newer and much faster processor than the Mac Pro I was using. That was to be expected.

Just as a quick comparison of how fast the iMac would export an H.264 vs. my Mac Pro, I took a 3:07 1920x1080 ProRes Quicktime movie and exported that as an iPhone formatted movie file using the similar setting for each application on both the 3.4 GHz i7 iMac and my 2.66 Ghz Quad Core Mac Pro. These types of comparisons must always be taken with a grain of salt as there’s many different factors to be taken into consideration including RAM, app versions, OS versions, effects applied, drive speeds etc. That’s a bit beyond what we will go into here but I think these numbers can give an idea of the difference in encode times for something editors often do, encode an iPhone-friendly H.264.

Final Cut Pro X - Share to iPhone with a quick color board color correction and a vignette: iMac - 1:53, Mac Pro - 3:08

Compressor - Apple Devices HD for Apple Devices 10 Mbps preset: iMac - 7:08, Mac Pro - 9:41

Adobe Media Encoder CS6 - a 960x540 23.976 preset: iMac - 1:31, Mac Pro - 1:57

Apple Quicktime X Player - Format iPad, iPhone, & Apple TV iMac - 1:39, Mac Pro - 2:21

Another obvious difference between an iMac and a MacPro is that an iMac has a fixed monitor size … and only one of them but that doesn’t mean you can’t add a second display. A standard editing configuration you see out in the world is a MacPro and two editing monitors. While a single 27-inch iMac is a thing of beauty I would consider it a must buy to tack on a second 27-inch display to match. With Apple’s Thunderbolt display it’s a simple one cable connection that delivers right through the Thunderbolt connection. While you might see some performance hits connecting multiple Thunderbolt displays that’s a rarity in traditional editing setups. I said above that I consider two editing monitors a must buy. On my two Mac Pro systems one has two 24-inch displays the other a single 30-inch. I much prefer the two 24’s when editing for any real length of time. Saving custom NLE window layouts across two monitors is a perfect way to work. Those editors working on a single laptop … you don’t know what you’re missing.

Up Next: About those brand new iMacs as well as the cost

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