Configuring an iMac Retina 5K for photo editing: tips


If you have been clinging to an older Mac Pro and are looking at potential upgrades, here are some notes on the iMac Retina 5K that might help you understand what to expect and what to order.

Processors. If you have been sitting on an older Mac Pro, you will simply want to go for the 4-core i7 at its maximum speed. The speed of photo editing software is much more dependent on simple clock speed than multithreading, and for this reason, the 4 x i7 iMac is probably going to be a better deal than the 2013+ Mac Pro. Let’s cut to the chase: the clock speed helps with Lightroom and Photoshop, and Adobe’s fear of multithreading means that you will want to go for the highest gigahertz figure. In addition, you cannot upgrade the processor later, so it is better to spend the extra $300 now.

Memory. The best configuration out of the box is 16Gb. This uses two slots and gives you the dual-channel speed you are paying for. Then buy two more 8Gb modules for $150. Then you are done forever. Hint: a child’s suction rattle is an excellent tool for removing the memory hatch, which is held in place by many spring clips.

Graphics unit. Don’t screw around on this part. A 5K screen requires a lot of capacity. Get 4 Gb of video RAM. This is another feature that cannot be upgraded later.

Screen: the most compelling feature about the iMac for photo editing is the 27″ wide, 5,000 pixel-width screen. It is like the Retina screen on an iPhone – just radically larger. The glossy finish helps blacken blacks (though it does sometimes show reflections). There are two effects of using a screen with this resolution, First, image files viewed 1:1 have an amazing clarity that makes it look like you are looking at the scene live – or looking at a good print. Second, you will need to look at many files at 2:1 to see what is actually going on in terms of sharpness, noise, etc. The screen on the 5K cannot be used as a secondary display for another Macintosh (and for good reason – they just don’t have the muscle to drive it). The system scales programs that are not optimized for 5K and manages to make everything work quite well.

Storage: unlike your Mac Pro, which could stash 12Tb on four internal drives (or a startup drive plus 3 drives making up a RAID 5), the iMac basically has two slots for storage. One takes PCIe flash memory; the other takes a 3.5″ desktop hard drive (or 2.5″ SSD with adapter). If you order the Fusion drive, you get a 128Gb card in the first and a 1-3Tb drive in the second. The two drives are linked as one logical volume via MacOS If you order straight flash memory, you get a flash drive that is 2x-4x the size (512Gb or 1Tb) and nothing in the HD slot (in fact, you don’t even get the connection cables). The problem with both of these arrangements is that PCIe memory wears out faster than hard drives, and the Fusion drive presents two independent paths to drive failure. Further, you are not really supposed to store your documents on the same flash/SSD drive as the startup disk and applications. All of this points to some kind of external storage solution. Consider using three drives:

  • Startup drive – this is the one in the machine. This should be an SSD, no question. Startup is 10 seconds; applications load and run immediately. This should contain a skeletal admin account so that you can start up the machine without any external drives if something goes awry.
  • User directories (really, documents). For reasons related to SSD wear and tear and general contention for resources, your user files should be an external drive – and preferably a bus-powered SSD. The bus-powered part is so that it can piggyback on a UPS serving the computer; the SSD part is so that it runs really, really fast (this makes a big difference with Lightroom’s Camera Raw cache and Mac mail). For backups, plan to clone the principal, mostly-static parts of your user account to the startup drive (or even documents other than space-intensive photo, video, and media files). The Library is the big thing you need, and you can exclude from the cloning files like web caches that change. Your main user directory should also be backed up via NAS to another device. The solid choice for this is the LaCie Rugged Thunderbolt SSD. If you look on Ebay, you can grab the 512Gb SSD unit for about $300, which is a steal, since it hits 400Mb/second through its Thunderbolt interface. You can get a Pegasus J2, but they are not nearly as fast.
  • Mass Storage Option 1: main storage on RAID 5. If you are doing a ton of photo work, you are going to need some large, fast drives. You will also want them to be reliable. The conventional solution is to use a RAID 5 system, which stripes data across a number of drives and records sufficient parity information to reconstruct a missing drive. Although this is more reliable, it is no substitute for a backup. When a drive fails, it can take many hours (or even days) for the missing data to be reconstructed. A second drive failure in the meantime generally means that you’re toast. And the total failure of the file system will wipe out everything on there. Consider instead the two-drive LaCie 2Big Thunderbolt 2 in the 6Tb size – in the striped mode, it runs in the 300Mb/second range for reads and writes. There are some even faster hard-drive-based units, like the Pegasus and the LaCie 5Big Thunderbolt 2, but these are much larger units that are designed for real-time video editing. They are also 4- and 5-drive budget-breakers, at $1,000 and up.
  • Mass Storage Option 2: main storage on RAID 0; backup on a NAS. Currently, Thunderbolt runs much faster than the fastest hard drive, so RAID o (pure striping) solutions are generally the best way to take advantage of some of the speed. The difficulty is that in a simple striped set, the failure of one drive takes everything down – and there is no way to upgrade capacity, The failure mode can be addressed by keeping cloned (or Time Machine) backups. In terms of capacity, you have to offload everything and then put it back on – but if you do that, you will already have fresh copies of your data on the off-loaded drives and backup of the machine on NAS. For the backup, I went with the LaCie 5Big NAS Pro diskless, which like the Synology and Drobo competitors has an intelligent RAID selector (SimplyRaid, a rebranded Seagate system) that allows you to incrementally expand the system by replacing one drive at a time. This is a big deal, since to expand a straight RAID 5 system, you have to offload all the data and then reload it onto the new array. This is why you should not buy a unit like the 5Big Network 2 – which in addition to being much slower, does not have the same expansion possibilities. The 5Big NAS Pro can also crank 60-90Mb/second on a gigabit ethernet line, which is an important thing to consider when you are running big backups over a LAN.
  • Incidentals – for dead storage or using up spare desktop HDs, check out the Sabio DM4LH Smart Raid 4-bay USB 2.0/eSata enclosures (RAID 0, 1, 0+1, 5, JBOD, Span). If you are sticking your Mac Pro in storage, you can yank out its 3.5″ drives and drop them in these well-designed enclosures and access them in JBOD mode. While the discontinued USB 2.0 version of this unit is not blazingly fast for massive transfers, you can get it for about $50 on Ebay and Amazon. Or you could plug its much faster eSATA connector into something like an Akitio Thunderdock. For more regular access, the USB 3.0 or Thunderbolt versions will be better. For single drives, MacAlly makes an enclosure that costs $75, looks like a mini Mac Pro (as if it’s a canopic jar…), and sports USB 3.0, Firewire 800, and eSata. It runs about $100. The version that has USB 3.0 and eSATA only runs $50.

Expansion: the typical silver Mac Pro has vast expandability, typically with (5) built-in USB 2.0 ports, (2) Firewire 800 ports, and (1) Firewire 400 port. It also has 3 open PCIe slots each of which can accommodate a card with up to four additional USB or Firewire ports or an eSATA bus. When you consider that the box itself holds 4 hard drives and 2 optical drives, the number of storage devices that can be connected to a Mac Pro without a hub is simply staggering. Some things to keep in mind:

  • Thunderbolt is far, far faster than anything hooked up to an old Mac Pro. Consider consolidating on larger devices with more storage. Yes, you could stick 15 Firewire drives on a single bus, but with drive sizes and RAID devices of today, you don’t need to.
  • Thunderbolt has a smaller device total limit than Firewire, and any device connected to the chain, however adapted (USB/eSATA/FW800) counts toward the total.
  • Some devices only fit the end of a chain (or chain plus adapter) – such as small external drives and some scanners (like the Nikon LS-9000).
  • You will eventually convert everything to SSDs and more modern devices. You might do this earlier than you anticipate.
  • Not all Thunderbolt interfaces are made equally. Some that have dual Thunderbolt and USB 3.0 connections run much closer to USB 3.0 speed.

The USB 3.0 ports will be exhausted faster than you think – an external DVD burner, a CompactFlash card reader, your iPhone cord, and the connection from your uninterruptible power supply (UPS) will suck up all four ports in a heartbeat. One bonus of the iMac is an SDXC card slot in the back of the screen/main unit, and it is plugged right into the PCIe bus – making transfers to the computer much faster than any USB 3.0 card reader. That said, its location is extremely clumsy.

If you need more storage and you’re willing to live with lower speeds, you can always plug USB drives into your NAS or your wireless router.

Keyboard and mice: the Apple wireless keyboard is compact, cord free (important given the USB port issue above), far more reliable than the old, full-size Apple Bluetooth unit, and very difficult to learn if your right little finger is used to touching the right side of any Apple Extended Keyboard. Consider whether you want to keep your old keyboard. The Magic Mouse is brilliant for photo editing because the gesture-based scrolling makes it easier to drag through huge Lightroom libraries, and the square edges make it easier to feel where to right click. Aside from that, the gestures do not help with Lightroom 5 or Photoshop CS6 – which do not support them. None of Apple’s current input devices will displace your Wacom.

Networking: for moving big pictures from networked storage devices, use the Ethernet port. Wireless is nice, but experience now demonstrates that not even AC1900 runs consistently as fast as gigabit Ethernet. One day, maybe. The actual connection speed is one issue – but the bigger one is these days, your computer is not the only thing competing for bandwidth on the router. With Ethernet, the detection, connection, and configuration of printers with their own IP addresses is much, much better.

Must-have software: aside from your usual image editing programs, here are three.

  1. The current version of Carbon Copy Cloner, which can be an important backup tool. If you have huge volumes of photos and use a nondestructive editor, Time Machine is dead-wrong as a backup method. The problem lies in a few things: (1) Time Machine is really designed to work with reasonable quantities of files that are changed from day-to-day (the largest thing with which you would trust it is your Lightroom catalog); (2) a Time Machine backup that contains terabytes of photographs will take days to initiate – and your main drive might fail in the meantime; and (3) Time Machine backups get screwy every so often and have to be redone from zero, which accentuates the risk in (b). With Carbon Copy Cloner, you simply clone your image file directories to another drive, either as directories and files or as sparse disk images. And if and when disaster strikes, you don’t have to try to do a selective restore from a Time Machine disk – you simply copy the files onto a new main drive and go on your merry way (actually, you could simply point your Lightroom library at the clone and keep working while you set up a new main drive).
  2. Mac Product Key Finder Pro. Migration assistant notwithstanding, many programs need to be re-initialized, re-installed, or re-registered when they are moved from one machine to another. It is also likely that you will not want to track every single box, sticker and serial number down from your software (this is an especially acute problem when your most recent Adobe product was an upgrade, and you can’t readily find the box for the original. This program scans your computer and shows you all registration codes and serial numbers.
  3. Contacts Cleaner. This is not imaging-related, but as you are getting your computing life in order in other ways, this will help rationalize, de-duplicate and generally improve the situations with your address book as stored on your iPhone and computer.

Migration advice: one advantage of using a dual USB/Thunderbolt device for your main storage is that you can consolidate all of your photos on that device. Your various SATA and Firewire drives’ data flows through your Mac Pro into the new box, which you then unplug from USB and plug into the new machine using Thunderbolt. Use Lightroom to effect the consolidation, and when you boot up your new machine, all you have to do (at most) is point Lightroom at the new mount point for your old drive.

As for the rest, expect some issues with Apple’s Migration Assistant. As noted above, losing product registrations is the big one. But also watch your permissions. The major reason to use Migration Assistant for your user directories is that it copies the unique identifiers to the new machine; it is a big trickier just to establish a user account on the new machine using your old user name. It is a very, very slow program.

In terms of how you move the data, it seems to be best to use the $29 Thunderbolt to Firewire 800 cable, with your old machine in target mode. Note that you may not be able to mount all drives in target mode, so think hard about other ways to migrate your big data collections on drives 3 and 4. If anyone tells you that Gigabit Ethernet is faster for these transfers, it is highly likely that he has not looked at the actual speeds that each protocol delivers. Firewire 800 on its worst day is better than gigE on its better days.

The bottom line: let’s not be indirect here – if you are replacing a pre-2013 Mac Pro, you can reasonably expect that making a meaningful improvement on its capabilities can easily hit around $5K total: about $3,200 for the machine; $300 for a secondary SSD drive; $150 for the extra RAM; 600 for primary storage; $500 (plus drives) for a NAS. It is still far less than buying a new Mac Pro with similar equipment, but wow. Once the credit card bills are paid, though, the Retina 5K is a great machine.

3 responses to “Configuring an iMac Retina 5K for photo editing: tips”

  1. Ulf Hansén says :

    Im about to buy a retina IMac

    Commin!g from PC world , I was googling for coniguration of retina IMac and I landed in your blog.
    I use my computer only förr daily email,reading papers paying bills etc.
    And very light word ,exel etc.
    I havet about 300Gb. Of pictures and just boughgt me a full frame nikon.
    I will start fresh on the new iMac with lightroom cc I havet played around with it on my PC,but nothing I ned to save.
    So its going to be a fresh startup on the mac ,but i dont have a clue how to configure the IMac .
    Its not going to be heavy lightroom or PS work ,bit my photo arkive is growing.
    I read your blog and wonder IF you have a suggestion for me
    Very best regards
    Ulf Hansén

  2. Mark says :

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  3. dominations hack says :

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