Photographer buying 27-inch iMac - which model?

Discussion in 'iMac' started by pavinder, Dec 30, 2013.

  1. pavinder macrumors member

    Jan 16, 2009
    I've read numerous threads on SSD vs Fusion etc, but still am not quite clear on which would be best for my needs.

    I'm about to upgrade from a 2009 24-inch iMac to a 2013 27-inch.

    I'm an artist/photographer and keep all my images (RAW and jpg, plus working PSDs) on external USB3 drives.

    I often do retouching work using an Intuos graphics tablet and Photoshop CS5/6. The photographs may have many layers and I usually use multiple mask and filter layers which when rendering (on my 2009 iMac) occasionally feels slow. I also use Lightroom and Adobe Bridge for organizing/simple editing.

    Based on my research, my understanding and basic questions are:

    1. If I have the 1TB fusion drive, when I'm in Photoshop the image I'm working on will be loaded into the SSD part of the drive and all processing will be done there, making my rendering etc. much faster than if I had the standard ATA drive - is that correct?

    2. If so, would there be any advantage at all (for Photoshop or Lightroom work) of having a SSD drive instead of the fusion drive?

    3. I believe the base level 3.2GHz model with GT 755M will be more than enough for what I do, and (as I'm not working with 3D, video or gaming) I wouldn't gain any benefit from the GTX 775M on the higher-spec machine - is this correct?

    Thanks in advance for your advice.
  2. pavinder thread starter macrumors member

    Jan 16, 2009
    To explain further, I have received 3 different explanations from different Apple Store staff members at various stores. They lead to 3 very different conclusions, and obviously they can't all be correct.

    The first explanation is that when you open an image in Photoshop the file will be loaded into the SSD part of a fusion drive, so all processing will be much faster than if you had the standard drive. These people said that there wouldn't be any advantage at all (for Photoshop or Lightroom work) of having an SSD drive instead of the fusion drive.

    ---> Their recommendation: fusion drive

    A second group of staff in Apple stores said this is not be the case at all! They said only the apps, system files and regularly used files are processed in the SSD part of the fusion drive, and that an image file being used by Photoshop will be loaded in RAM (so whether I have a fusion drive, an SSD or a standard HDD is irrelevant).

    They said the only advantage (for Photoshop) of getting an SSD would be if all my image files were stored on it. The drive would only be used during opening/saving anyway. So according to them, if using externals for storage, there is absolutely no need to get a SSD - the "SSD part" of the fusion drive will be enough.

    ---> Their recommendation: (mostly) fusion drive

    A third group of staff disagreed with both of the above! They said that once the app (Photoshop) was open, absolutely everything would be done in RAM (both the image file and the running of the app) - they recommended I save money and just buy the standard drive. They said that aside from file opening/saving speed, neither the SSD nor the fusion drive would make "any significant difference" compared to the standard drive, as both the image and the app will now depend solely on the speed of RAM processing.

    ---> Their recommendation: standard HDD drive

    Obviously these 3 different views cannot all be correct.

    Could anyone please explain the facts? Thanks in advance.
  3. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    I'd say go for a pure SSD out of reliability and pure speed. The Fusion still has a HDD sector and if that fails (which is as likely as a regular HDD), the entire drive is toast and everything is lost. You cannot just operate off the SSD sector.

    And for speed, in terms of read/writes:
    Fusion: 520/350 MB/s
    SSD: 750/650 MB/s

    When you load an image and work on it in Photoshop, it's all loaded to the RAM (memory) from the hard drive (which can be HDD, Fusion or SSD). How fast the image loads to the RAM is dependent on the hard drive, with SSD being the fastest and HDD being the slowest. The most frequently used images in Fusion are moved to the SSD parts and hence will load to the RAM fastest, while the least frequently used images in Fusion are stored in the HDD parts and hence will load to the RAM the slowest.
  4. pavinder, Dec 30, 2013
    Last edited: Dec 30, 2013

    pavinder thread starter macrumors member

    Jan 16, 2009
    Thanks for the comment. Given that all my images are on externals, and I generally do all my work on an image in one session, then the idea of "frequently used images" being moved to the SSD won't happen in my case.

    So it sounds like the fusion or SSD wouldn't make any difference at all, right? So the image file itself AND all the photo editing, applying of filters/rendering in fact happens in RAM?

    I agree that there may be more "pure speed" in opening/saving files and opening the apps, but in actual processing and editing speeds there will be no difference between SSD and basic HDD?
  5. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    I have no idea why would you want to work off an external drive anyway, it's slow. I shift whatever I want to work on to my SSD and after I'm done, I shift it back to my external storage (a Promise Pegasus R6).

    Oh and if you want to see how fast my SSD iMac boots:

    A HDD iMac will take one to two minutes to get into a usable state. With an SSD, it immediately goes into a usable state after logging in.
  6. pavinder thread starter macrumors member

    Jan 16, 2009
    I have SSD on my other Macs, so I know how fast startup/shutdown/opening/closing files and apps can be. Blazingly fast - I love it.

    But my questions here are specifically regarding what determines the speed of processing of image files in Photoshop once they are open. From what I can make out based on your previous comment, are you saying that SSD/fusion drive would make no difference to this whatsoever as everything is done in RAM?
  7. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    Not too sure about that. But one thing is sure, you wouldn't want a 5400rpm drive no matter what you're doing.
  8. 2trout macrumors member

    Nov 2, 2013
    for me its pretty much a no brainer, SSD.
    If you are happy paying the extra $ for an SSD, by the way, their prices have dropped dramatically, and still keep doing so, then don't think about, just do it.
    With the exception of our recently acquired iMac, all our other Macs as well as PC's run on SSD's, night and day over 'conventional' HD's!
  9. pavinder thread starter macrumors member

    Jan 16, 2009
    Maybe this is the most relevant point (from the Adobe support pages):
    So on this basis, as long as there's far more RAM than the size of my images, installing extra RAM would be a better option for faster Photoshop work than buying a fusion or SSD drive, right?
  10. joema2 macrumors 68000


    Sep 3, 2013
    I have a 2013 iMac 27 i7@3.5Ghz, 32GB RAM, 3TB Fusion Drive, also use a 8TB Pegasus R4 in RAID 5. I use Lightroom 5.3 and Photoshop CC, and FCP X, although I use Premiere Pro CS6 on my Windows machine. I have about 60 terabytes of external storage on a variety of USB 3 and eSATA drives. Some of the USB 3 drives are bus-powered portable drives, some are AC-powered.

    There is a huge difference between performance of various USB drives. Some are 5400 rpm, bus-powered, some are 7200 rpm, some are AC-powered 5400 rpm, some 7200 rpm, some have lots of internal cache, some have little.

    Also the disk format used makes a difference, whether FAT-32, exFAT, or HPFS+.

    The slower the external drive, the more important it is to copy that to internal storage before doing lots of work. You can edit and work off a fast external drive, but not a slow one.

    The importance of I/O performance varies widely based on what you're doing. Certain LR/Photoshop actions are disk intensive, others are CPU intensive. Improving a system element which isn't a bottleneck won't help any. E.g, if your main task is CPU-bound, making the disk faster won't help any.

    You can tell whether your activity is I/O or CPU-bound by running it while watching Activity Monitor. The 3rd party utility iStat Menus lets you monitor independently the I/O to the SSD portion vs the rotating portion of the Fusion Drive:

    Whether you have SSD or rotating storage, it must be backed up. In that sense the theoretical difference in reliability matters less.

    In general I've found the 3TB Fusion Drive very fast and convenient. It gives much of the performance of an SSD without the space and management hassles.

    Your personal workflow, combined with amount and type of image material makes a big difference. I often have to ingest and catalog 80GB of raw stills and video per day. In that case the highest I/O performance is important. OTOH if you work with 10's of photos but spend an hour each on them, I/O performance is maybe less important than CPU or GPU.
  11. pavinder thread starter macrumors member

    Jan 16, 2009
    Thanks for an incredibly helpful reply - very much appreciated.

    I'm very interested to hear of your choice of the 3TB fusion drive, and that it's working well for you. It makes a lot of sense to have a fusion drive which has much more space, but with the speed benefit of 128GB of SSD. I had considered a 256GB SSD drive, but your recommendation of copying to internal storage before doing lots of work would probably start pushing the limits of capacity if I wasn't careful.

    What you say about different LR/Photoshop actions being sometimes CPU-intensive and sometimes disk-intensive is very valuable information. I have iStat but haven't been monitoring different actions to see what does what. I definitely will now.

    Based on what you describe, the volumes of work you process exceeds mine by a large factor. I'm mainly working on 200 or so shots a day, many just need basic edits but a few of them will be worked on for a lot of time and get very big with tens of layers. That suggests CPU rather than I/O will be my priority.

    I'll install the maximum possible RAM as soon as I get the machine, and as far as I can gather, an upgraded graphic card won't make any difference.

    But do you think that the 3.5GHz i7 would make a big difference over the standard 3.2GHz i5, given that I'm editing image files (for the most part one at a time) but not doing anything with 3D, video or games?
  12. AppleFan360 macrumors 68020

    Jan 26, 2008
    No question. Get at least a Fusion drive or pure SSD if your funds allow. I have a 1 TB Fusion drive and edited a 2 hour long wedding video in Final Cut Pro X without even a hiccup and rendering time was FAST. Granted, you will be working with photos but the same concept applies.

    Pure SSD's are expensive and they do fail eventually. Like standard spinning drives, they have a limit on read/write cycles. Don't let the myth of realiability get into your head concerning SSD drives. Fusion drives have a lot more space, less cost and offer the luxury of SSD speeds. Also, using an external drive array will also speed things up (two or more drives running together as one).
  13. joema2 macrumors 68000


    Sep 3, 2013
    I have the i7, but IMO hyperthreading is of limited benefit -- when compared with other improvements, given a fixed budget. If you can afford the i7 without sacrificing anything else, then it's OK. On certain multi-threaded CPU-bound tasks, it might improve perf. by 15% or so. But a faster disk subsystem (like the 3TB Fusion Drive) will help many activities in a more noticeable way.

    The current top i5 iMac is 3.4Ghz, with Turbo Boost to 3.8Ghz.

    In general the GPU isn't used that much on Photoshop CS6. It does speedup a few items, but not that many. The issue isn't whether a benchmark number is higher, it's whether you can easily perceive a difference in your specific workflow. My 2013 iMac has the GTX-780M with 4GB, my wife's 2012 i7 iMac has the GTX-675MX with 1GB. I've done a few side-by-side Lightroom import/export/render tests, and I can't tell any difference due to the GPU.

    However it's important to be very specific about your work items. Certain effects or filters might be accelerated by the GPU more than others. This can vary greatly from version to version.

    E.g, say you spend lots of time using the Liquify filter or in CC the new "shake reduction" sharpening. Liquify performance was hugely improved from CS5 to CS6; I think it uses the GPU better. Photoshop CC shake reduction slider changes are sluggish on my 2013 iMac with GTX-780M, but also are sluggish on my 4Ghz i7-875K Windows 7 PC with a GTX-660 (2GB), which has much higher GPU performance.

    Try to evaluate the specific item(s) in your workflow that seem slow now. Ideally derive a simple test case and get a friend to test those on another iMac, or take it to the Apple store and test it yourself on different machines. That way you'll have first hand experience whether it's worth paying for the extra hardware.

    In general I'd suggest the 3TB Fusion, also use only USB 3 external drives (never USB 2). Even USB 3 drives vary in speed -- the AC-powered USB 3 drives are generally much faster than the bus-powered drives. There is likewise a huge difference in I/O performance of various USB 3 memory sticks.

    However nothing wrong with the SSD options -- they are just smaller and more expensive. But if they fit within your size and financial budget, they are even faster.

    As already suggested, it may be better to copy incoming work to a faster internal drive, do work there, then copy the final results to an external drive.
  14. dld542004 macrumors newbie

    Jul 11, 2008
    which drive

    My suggestion is increase the memory yourself and select the 3TB Fusion drive use an external drive for backup.
  15. phrehdd macrumors 68040


    Oct 25, 2008
    There are some things you never mentioned -

    Exactly how much space does your OS and all the applications installed take up?

    Are you going to consider RAM implications? CS6 PS loves RAM and it makes a huge difference with complex or large projects being worked upon.

    Though SSD is faster than Fusion, Fusion offerings are available in larger sizes.

    In general, I find the iMac not the best choice for Photoshop work due to the screen. Avid PS users know that screens should be calibrated on a regular basis and have a decent gambit to handle all sorts of image files. If you are only doing restoration from prints, iMac will be a fine option if you can master the calibration facets. If you are doing retouch/restoration from original film and digital images, the screen is a bit lacking as compared to say an NEC PA series monitor. If printing is in the equation, then you need to get both* the screen and the printer calibrated and iMacs are well... again a bit lacking compared to the alternatives out there.

    I'll skip the comments on glass/glare issues as everyone's eyes are different and their environments.

    If you are sure you want the 27" iMac, max the RAM and you'll find either the SSD or the Fusion to be faster than what you have presently.
  16. jcr918 macrumors regular

    Nov 8, 2012
    I do a lot of photo editing my raw files from my 5D Mark III are huge. My macbook pro retina does a decent job currently it's i7 16gb ram with solid state so I think the imac should do better I am getting this 27" imac

    3.5GHz Quad-core Intel Core i7,
    32GB RAM
    3TB Fusion Drive
    NVIDIA GeForce GTX 780M 4GB GDDR5
  17. pavinder thread starter macrumors member

    Jan 16, 2009
    Thanks everyone for the valuable feedback.

    I've decided to go for the fusion drive, just now doing a bit more checking/monitoring of LR/Photoshop processes as suggested to decide whether a faster processor might be worthwhile.

    As a few people suggested and I was already planning, I'll get extra RAM from a third-party supplier and bump that up to 32GB.

    I'm still on CS5 for most use, but definitely want to be prepared for a future upgrade to CC, so will keep your points in mind.

    My System/Apps/Library take up around 50GB, but add 150GB of User/documents and I think I'd only consider an SSD if I could get the 512GB - I imagine prices will drop so I'll wait for that until my next upgrade.
    Print calibration - that's something I don't try to tackle myself, on the occasions I need print I take work to a professional lab. As far as the iMac screen goes, yes, your point is well taken. I do have access to a high-level monitor/Mac Pro at a studio, so the iMac will be for home use. I'd love such a setup at home too but simply can't justify the cost.
  18. joema2, Jan 1, 2014
    Last edited: Jan 1, 2014

    joema2 macrumors 68000


    Sep 3, 2013
    The main point was your screen (whether Mac or 3rd party) should be calibrated. This isn't difficult or expensive to do. ColorMunki Photo will do screen alone or both screen and printer for about $450. You can use it on more than one computer:

    Without a calibrated screen you don't have full confidence in the editing changes. It is easy to invest many hours in photo adjustment, only to realize they are all off due to a mis-calibrated screen.

    I have a 27" Dell Ultrasharp U2713HM on my Windows PC. Both it and my 2013 iMac 27" are good screens, although there are better ones available. However no screen is trustworthy unless it's calibrated and that calibration maintained. In this topic the main point got blurred. It's far more important to calibrate the screen you have than to get some theoretically better screen.
  19. cocky jeremy macrumors 601

    cocky jeremy

    Jul 12, 2008
    Columbus, OH
    Photographer here that just bought a 27" iMac. I went with i5, 512 GB SSD, and upgraded the RAM myself.

    You'll mostly be using LR/Aperture and PS, I'm guessing. RAW files take up a ton of space, but those apps open slowly on a regular drive, so I went with the SSD and a USB 3.0/Thunderbolt external drive to store my RAW/JPEG files.

    The i5 is plenty for processing the files. Upgrading RAM is a big one, but it's much cheaper to do through Crucial. As of now, I'm sticking with 24 GB. (Two 8 GB sticks, two 4 GB sticks)

    I'm having no issues at all. Super quick to import, process, and export. I export one image every 1-2 seconds. Same for importing, and no lag at all while editing.

    Hope that helps.
  20. jcr918 macrumors regular

    Nov 8, 2012
    I think the fusion drive is diffidently a better choice. Read speeds are faster then older SSD write speeds are slower. I get about 480 read on my early Macbook 2013 pro retina with the fusion Ill be getting 500 + but slower read but not much.

    In the end I doubt most people would notice. The only concern I have is the fusion drive failing but I got AppleCare ordered so if my 3tb fusion fails ill get a new one.

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