IMac Edit system for FCPX

[Joe Marler]

[Scott Witthaus] “He is looking at an iMac and a Pegasus Raid array to hang off of it. Should I just have him buy the iMac that is tricked out on everything or are there certain items I need to make him aware of? Dissuade him from the iMac and go with a MBP?”

That is a good combination, which I formerly used. I have a top-spec 2015 MBP and don’t use that for editing unless I’m in the field and cannot avoid it. For extended editing sessions, a top-spec 2015 iMac 27 is much better — quieter, faster, bigger screen, etc.

The Pegasus arrays are good but (like most hardware RAID boxes) you are locked into their proprietary format. If the chassis itself goes down, the drives can only be used in another Pegasus. By contrast something like an OWC Thunderbay 4 using SoftRAID is just as fast and in a chassis failure scenario the drives can be used in any other drive enclosure.

Spinning RAID arrays have good sequential I/O performance but FCPX does a lot of random 8k I/O when building and maintaining thumbnails and plist files for the Event Browser. RAID arrays are not good at small random I/Os. If he can afford it, an 8TB OWC Thunderbay 4 Mini with 4 x 2TB Samsung EVO 850 drives in RAID-0 is about $3k and delivers over 1,100 MB/sec plus vastly higher random I/O performance. Unlike spinning RAID arrays (indeed all spinning drives) SSD performance does not drastically degrade as the drive fills up.

Obviously any disk storage should also be backed up, so he’ll need (at a minimum) 2x his total storage to include backups.

A top-spec 2015 iMac 27 is certainly adequate for editing 1080p and 4k H264, but if the updated iMac should be out pretty soon. If I were in his shoes I’d consider waiting for that, or if that’s not possible getting a less expensive refurbished iMac until the update is ready. The update probably won’t be much faster from a CPU standpoint but the GPU will probably be considerably faster.

[Nick Toth]

I have a spinning platter Thunderbay and it consistently reads and writes faster than my Pegasus 2. Slows down as it get full like most spinning RAID’s so get the biggest one you can if you choose to go that route. FWIW

[Scott Witthaus]

Thanks for the input!

Scott Witthaus
Senior Editor/Post Production Supervisor
1708 Inc./Editorial
Professor, VCU Brandcenter