I’ve used Mac workstations since the early 1990s. As a professional photographer, it’s important to have a computer that is not only fast, but also scalable. For me, that meant being able to add internal hard drives, PCI expansion cards, and plenty of RAM. By having a computer that I could incrementally upgrade, I am able to extend the useful life of that machine. As a working professional, I consider upgrading my computer system every 3-5 years, depending on my needs.
In 2013, Apple radically redesigned the Mac Pro line to include internal PCI-based solid-state drives and dual video cards. Despite the performance benefits, the new form-factor no longer supported internal expansion of any kind (other than RAM). Although I was not in the market for a new Mac at that time, the immediate consequence of the new form-factor became clear. From now on, any hard drives that lived inside my existing computer would have to be moved to external enclosures.
Apple’s decision to alter the Mac Pro’s form factor suddenly made me start to look at the iMac as a possible future replacement. After all, I’d have to get external drive enclosures either way, as well as a PCI enclosure for my solid-state drive (SSD). My only concerns were processor performance and memory capacity.
I already knew that the Intel i7 processors in the iMac were plenty up to the task of running Lightroom and Photoshop, because that’s the same type of processor that runs my MacBook Pro. It was the 32GB RAM limit on iMacs that had me most concerned. However, when Apple announced the latest update to their 27″ iMacs with Retina display in October, not only did the processors get upgraded, but it turned out that these new iMacs would support up to 64GB of memory. You just need to order the memory from a 3rd-party vendor other than Apple; something I’ve done for years anyway. After much deliberation, I decided to go with the 27″ retina iMac (late 2015), which I ordered from B&H Photo. B&H is an authorized Apple retailer, and you can purchase an AppleCare warranty from them, too (something I highly recommend).
My iMac System
- 4GHz i7 “Skylake” processor
- 8GB memory (which I upgraded to 48GB from here).
- 512GB internal Solid State Drive (this drive only needs to hold my system and applications; all other data are on separate drives)
- AMD Radeon R9 M395X graphics (4GB DDR5 memory)
What about my existing hard drives? Well, I already had a 16TB RAID 5 array for photos in a USB 3.0 enclosure. I picked up a 4-bay Thunderbolt 2 enclosure and an OWC Helios PCI enclosure. I put my internal hard drives into the USB 3 enclosure, and moved the 4-disk RAID set into the Thunderbolt enclosure for even better speed. Note: I set up my RAID using a software utility called SoftRaid. If you have a hardware RAID enclosure you can’t move the disks out of it without breaking the array. With SoftRAID, the RAID 5 array was recognized even though it was in a new enclosure. My existing PCI-based SSD went into the Helios enclosure, and I’m using it as a super-fast scratch disk for Photoshop.
First Impressions: Display
The big deal with these 27″ iMacs is their amazing “5k” Retina display, with a resolution of 5120 x 2880 pixels . The late 2015 models use a different LED backlight technology from the earlier models, one that is supposed to offer a wider color gamut. I calibrated and tested the display with my Spyder 4 colorimeter, and sure enough it measured at 92% of the Adobe RGB color space. I figured this would be no big deal. I was wrong. Suddenly, my other displays looked fuzzy and greenish (despite being calibrated) when viewed next to the iMac. Imagine an iPad or iPhone screen that’s 27″ wide. That’s what this display looks like. Considering that a similar 3rd-party display (and don’t get me wrong, there are good ones out there) would easily cost upwards of $1500, that’s a HUGE value with the iMac.
Performance Benchmarks
Frankly, you don’t see the kind of screaming speed improvements with a new computer these days like we did in the 90’s when it seemed like processor speeds doubled every year or two. But I did run my normal suite of tests just to see how it compared to my previous system, a 6-core, 3.33 GHz Mac Pro Xeon workstation, and I was pleased.
Geekbench 3 Scores
In both tests, the iMac running its 4GHz i7 processor beat my 2010 Mac Pro. Single-core tasks were, in fact, 58% faster with the iMac. Not surprisingly, the 6-core machine held its own in multi-core tests against the 4-core iMac. For most photography software, single-core performance will usually be more beneficial than multi-core performance. The notable exception would be video production, which can really get a boost from multiple processor cores. Of course, the Geekbench tests are arbitrary processor benchmarks. Therefore, I also tested Photoshop performance using Lloyd Chambers’ Diglloyd Photoshop Benchmarks.
Photoshop Tests
The Diglloyd benchmarks are useful because they are a repeatable set of Photoshop actions that can be used to compare computer performance doing “real-world” operations like image rotation, blur, sharpen, etc. Here’s how the two computers compared with the three most applicable tests:
In all three of these tests, which run on normal-sized files photographers would be expected to encounter, the iMac beat the Mac Pro. The iMac ran about 25% faster in the “Speed 1” test but only about 14% faster in the “Medium” file test. Again, despite having two fewer processor cores, the iMac handles Photoshop perfectly well. I also haven’t had any issues running Lightroom CC 2015 with the iMac. Even the spot healing tool in visualizer mode is responsive; something that wasn’t always the case with my previous Mac Pro.
Conclusion: Photographers should consider the new iMac
The combination of fast processors, an upper limit of 64GB memory, and a beautiful 5k “Retina” display with a wide color gamut make the iMac a very attractive option for Mac-centric photographers. A comparably spec’d Mac Pro system would cost nearly $7000, and still wouldn’t be faster in many single-core tasks (the multi-core Mac Pros run slower clock speeds). The Mac Pro is essentially a video producer’s dream machine, but for everyone else, I think you’ll be really happy with an iMac system.
Here is the iMac configuration I purchased, from B&H Photo (Save on sales tax outside NY). I was able to use the money I saved on sales tax to help pay for the external drive enclosures from OWC.
I strongly recommend getting an internal SSD for maximum system performance. You can store your photos, music, and mail on external hard drives. Not only does this speed up boot and application launch times, but it also allows you to boot your computer from a different drive and access your data should your internal drive fail.
I purchased my memory from OWC at a significant discount compared to Apple memory. I’ve had no issues with RAM from OWC, ever.
Shop Apple iMacs & B&H and pay no sales tax outside of NY
Jason, with this new iMac, what calibration system do you use?
A this moment I use an early 2009 Mac Pro, upgraded with PCI SSD-512MB and Eizo display. For a while I have been thinking what will be my next step, iMac with glossy screen with calibration issues….., new Mac Pro, too $$$ and overkill for photography IMHO. So your write up comes in handy and on time, thanks! Good point to use my SSD in a Helios as a scratch disk. Two questions: where does the LR catalog live, internal SSD pictures folder? And how to move mail on external drives, is that possible and easy to manage? – Fred
Hi Fred-
I went ahead and moved my LR catalog from my OWC SSD to the internal Apple SSD. Moving Mail to external drives requires a few steps, but it’s not hard. I followed the instructions on Lloyd Chambers’ site: Moving Mac Mail off of the Boot Drive
I used my Datacolor Spyder 4 system.
Do you think it is really important or makes a difference to choose the 4 gb graphics instead of the 2 gb?
I think the 4GB graphics card is most useful if you’re going to be doing video work or running multiple displays. For most users, the 2GB graphics option should be fine.
Hi Jason, thank you for your review. I am very interested in getting the late 2015 iMac. The only potential problem I know of is that it may be difficult to properly calibrate the 5K screen for purposes of printing images or distributing them where they may be viewed on a screen with a different color gamut. I came across this commentary regarding the 5K screen from diglloyed- http://macperformanceguide.com/iMac5K_2015-colorGamut.html. Have you seen this issue with any of your printed images? Dave
Hi Dave-
When sharing images, I always save my JPEGs with the sRGB profile, so I haven’t seen any issues whatsoever. If you have a calibrated monitor and are soft-proofing for print, you should be just fine.
Excellent article! Jason, when you save/convert your images to sRGB to share with others, do you have to tweak those images in sRGB beforehand to bring back the saturation level you created in the wider color gamut? I’ve been debating whether to buy the P-3 iMac to enjoy the truer, richer colors of my nature images or rather to just buy one of the ‘old’ 2014 or May 2015 sRGB versions to avoid extra work in exporting to the web or for commercial printing. I’ll be posting hundreds of images on my website and it seems that with a wider gamut screen, I would have to photo edit in the soft-proofed sRGB color space anyway in order to evaluate and choose which images to display and sell on the internet since most other people will not see the wider color gamut that I will see in the P-3 color space. So it seems that the wider gamut becomes sort of irrelevant if I can’t use it professionally.
I sometimes tweak the files using soft-proofing in sRGB, but the issue is that sRGB will always have a smaller gamut range… you usually just don’t notice it. I still saw slight differences in saturation even using my previous displays, so it’s just something to be aware of. However, I haven’t had any major issues so far.
Hi Jason, I am now at the stage I am upgrading to an iMac 21inch i7 3.3Ghz 16GB. At present I store all my photos on an external hard drive as my 7 yr old Laptop is extremely slow. I edit my photos on LR lite on my iPhone but will look to install LR on the iMac.
Can I retain all my photos on the existing external hard drive and connect it on the iMac? For speed of photo editing do I go for the 2TB fusion drive or 512GB flash storage ?
Thank you for a great article!
Loretta MacGregor
Hi Loretta-
I have my iMac set up to store all my photos on external drives. It’s much easier to migrate things that way. One thing I’d recommend is upgrading the external drive enclosures to either USB 3.0 or Thunderbolt, which will speed things up a lot compared to older interfaces.
I think that as long as you store the bulk of your data externally (photos/music, etc.) Then a 500gb SSD is plenty for a primary “boot” partition. The only stuff I keep on the internal SSD is the OS and my application software. That leaves plenty of room for scratch disk use etc.
Thank you for this post which is directed at photo/video editing users. I have an iMac 27″ and am wondering if I should upgrade to the AMD Radeon R9 M395X graphics card. I do primarily photo editing with Aperture, Photoshop Elements. I know I can’t hang onto Aperture forever, and I hear that the trend is for photo editing programs (Lightroom, etc.) to use more and more GPU power in the future. Should I upgrade to the 4GB graphics card to help improve the longevity of my iMac? I hope to keep it for as long as I can.
Hi Adelia-
I think that in terms of general speed, the better video card doesn’t really offer a huge improvement. What it *does* do, however, is significantly speed up things like video export (Final Cut/Compressor) and the ability to use more advanced graphics settings in Photoshop. The biggest benefits will be from adding max RAM and getting the fastest i7 processor in the iMac.
Hi Jason,
Thanks for the great post. I am seriously considering making the PC (Windows 10) to iMac conversion for my photo processing and your article really helped. I have one question, for processing I use Nikon View Nxi, Lightroom & Photoshop (Creative Cloud package.) I have approximately 2 TB of .nef files I would like to transfer over to use on a new iMac with an external hard drive such as yours. What would your recommendation be to transfer everything over?
Hi Bob-
Assuming the NEFs are not currently on the external drive… What would probably be easiest is if you exported your existing LR catalog to the new external drive, along with the images (negatives, as LR calls them). This will preserve your existing directory structure on the new drive. Then, connect the external drive to the new iMac and import the LR catalog you created (or just open the LR catalog from the drive itself). I’d recommend putting the LR catalog on the fast internal drive and keeping the images on the external drive(s).
Hi Jason
Great post and many thanks, recently iv made the move from an older mac pro to the new 27inch iMac, maxed out with i7 processor, the better video card 64 ram and a 1TB apple flash drive the photoshop scratch is on the 1TB apple flash drive with my apps, p-shop/lightroom etc which still has over 700gb free but i feel photoshop and lightroom are a bit laggy and slow at times, do you think a separate scratch disk would help in this case and if so what would you recommend. cheers john t
John- some of it certainly has to do with driving the 27″ retina display. Here’s Adobe’s notes on LR performance: https://helpx.adobe.com/lightroom/kb/optimize-performance-lightroom.html