macrumors regular
Original poster
Jan 14, 2013
This is a frustrating topic to research and has become a bit of an argument among my videographer friends.

My suggestion has been: keep your current project on the internal FAST SSD. Finish it. Save it to your external HDD. Surely editing video footage that's stored on the internal SSD will prove to be a faster experience than editing footage stored on an external HDD. The current SSD in the skylake iMac reads at nearly 2gb/s vs. an external hdd that reads at 230mb/s or less.

But many insist you'll get faster performance by keeping all your footage on an external hdd. Just doesn't make sense to me.

Now some say, if you use your internal drive with FCX the drive will fill up too quickly. But I'm suggesting you only keep your current project stored on the internal drive, nothing more. Not your iTunes library, nothing, just your current project.

PS - if your projects are hollywood, yeah I'm sure they'll exceed the 1tb internal drive. So in that case, of course you need external, I get it :)



macrumors 68040
Feb 10, 2008
If the project library fits on the internal drive, things are good. Next best is a SSD on the thunderbolt bus. If you must do HD, then at least RAID0 two or three, but spin up and access times can slow you down.

I found that no matter how careful I was about saving space, eventually I run out of internal drive space and then spend extra time moving things around. FPX libraries can grow in size just setting there :)

For best performance on short term projects, I have evolved to setting up the library internally but all the source media on external SSDs (TB). Leave the media there, don't import them into the library. For longer term projects, I put the library on a external SSD, still keeping the source video separate, sometimes on a RAID array.
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macrumors 68000
Sep 3, 2013
Standard practice for video editing is don't put your media on the boot drive. The idea is split the I/O load since the boot drive is already handling the OS, paging file, apps, etc.

However this viewpoint was established before hyper-fast SSDs existed like the 2015 iMac 27. That is probably fast enough to handle the OS and 1080p or even some 4k video editing.

That said, 1TB is not that big after you subtract the OS, apps, etc -- esp. when considering the hidden I/O often required for video editing. There can be scratch files, render files, optical flow files, optimized media files, etc. If you are shooting 4k multiply all that by 4x.

The other issue is whether you need that much I/O performance anyway. If editing H264, many common video editing tasks are CPU or GPU-oriented not I/O. The entire purpose of long GOP formats like H264 is to limit I/O so it fits on a broadcast channel or camera media card. That same I/O reduction applies if you are editing camera native files. Both Premiere and FCP X are good at editing 1080p camera native files. 4k is another story.

OTOH if you acquire in or transcode to lower compression codecs, then I/O will be much higher -- but so will space requirements.

E.g, a 52 sec H264 4k test clip is about 140MB out of the camera. To play this file in FCP X produces an I/O rate of 2.8 megabytes/sec.

Yet that same file if acquired in or transcoded to ProRes 422 becomes 3GB and produces an I/O rate of 58 megabytes/sec. Only one hour of material in that format would be 208GB, and there could be lots of other space required for various temp, scratch and render files.

A typical shooting ratio for documentary-style production is 30 to 1, or 30 hrs of shot material for 1 hr of final product. If your product is only 15 min long, this would still equate to over 7 hr of shot material. That standard partially comes from the film era. With digital cameras, shooting ratios can be much higher, even for small productions. All that material has to live somewhere while it is being edited. David Fincher's movie Gone Girl used a 200 to 1 shooting ratio, or 500 hours of material shot to produce a 2.5 hr movie.


macrumors 68040
Oct 25, 2008
Seems that people often merge, combine or confuse work space with storage space. Chances are, as was well explained by others here is that quite a bit of work space is needed to comfortably edit video. Given this, the internal drive may not be sufficient in space though it does meet (SSD) the throughput-I/O requirements. It would make sense to look at external options that are connected via Thunderbolt. Some options might include SSD but many consider RAID 0 with typical electro-mechanical drives to be a reasonable solution. Since RAID 0 is not redundant, a wise option might be to do either both stripe and mirror (4 drives min) with a hit in speed or, continue with stripe only and do some backups to other drives manually or via script. A good Thunderbolt DAS seems to fit the need with fast quality drives with the only true constraint being budget. Areca, as example, offers some excellent options as well as a few other makers that are worth investigating.

My take would be to do a combo of striping and mirroring and accept a slight speed hit. You can look up the differences between RAID 10 and RAID 01 (or in some circles 0+1). (hint) One of the latter, provides for greater drive failure protection. A nifty setup might be a 6 drive combination - 4 drives to do as above, 1 drive on standby for failures and the last drive to be larger and not part of the RAID set up as a static backup (usually a much larger slower drive).
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