iMac 2.5k MAX vs iMac Retina 5K

Discussion in 'iMac' started by Maric, Feb 21, 2015.

  1. Maric macrumors newbie

    Dec 13, 2014
    Hi guys,

    I want to upgrade to a iMac but I can't seem to figure out which model to buy.

    What do you guys think:

    NON Retina 27'' iMac :
    CPU: 3.5 turbo boost up to 3.9Ghz
    Storage: 1tb fusion drive


    Retina 5k 27'' iMac :
    CPU: 3.5 turbo boost up to 3.9Ghz
    Storage: 1tb fusion drive

    The big difference is in the graphics department of course but I am not sure which one will be faster.
    I am planning to mainly use the machine for ( pretty ) professional After Effects / Final cut Pro work and maybe some lite Cinema 4D ( 3D ) modeling.

    I mainly work with 1080p video at the moment but I am planning to upgrade to the Sony GH4 ( 4k video ) in the future.

    I think the display on the NON Retina iMac is very nice even though it isn't as high resolution as the 5k iMac. I also think that because I'm mainly using 1080p video I won't benefit of the high pixel density anyway...( I do believe it looks very nice though! )

    What do you guys think is the best choice for me? Will the NON Retina iMac outperform the retina iMac because of the 4gb VRAM, or is the AMD stronger?
    Or is the iMac perhaps slower because the graphics card has a hard time pushing all those pixels?

    I hope someone will reply soon!


  2. BrettApple macrumors 65816


    Apr 3, 2010
    Heart of the midwest
    I'd imagine the non retina iMac would perform better since it has far less pixels to push. The 780m is a pretty good card as far as mobile cards are concerned. It looks like it's more powerful than the Radeon R9 M290X actually.

    The retina screen is pretty amazing though, but if you don't need it, the non-retina would be the winner here.

    If you have the cash, you could also go full SSD and use Thunderbolt/USB 3 external drives for media if you want it to be even faster. The Fusion drive is nice, but full on SSD is better. But smaller of course. Added benefit of not having an internal hard drive to fail though. They aren't that easy to get open and replace if you're a DIY kind of person that is.

    So my vote is for the non retina model, performance wise.
  3. WilliamG macrumors G3

    Mar 29, 2008
    The 5K screen is awesome ALL the time. People seem to forget that part. I've not done a shred of video editing on my 5K iMac, and the screen is still stunning.
  4. aevan macrumors 68030


    Feb 5, 2015
    Depends what you plan on doing on your iMac.

    For simplicity sake, let's say they are similar in performance. Yes, the 5K has more pixels to push, but for gaming, you simply won't play games in 5K or 4K, so that's not an issue. And in non-retina resolutions, they are both quite fine and similar. 780M is a bit faster on paper, but that's compared to the regular M290X, and the iMac version is clocked higher. I'd say they are close.
    For productivity, it does get more demanding in 5K at times, but the boost in picture quality is worth it. In fact, for most of these tasks, the CPU is actually getting taxed more than the GPU. For example, Lightroom has to calculate all the previews in much higher resolution and that makes it a bit slower as the CPU has more work to do - on the other hand, you get to see the sharper photos and with much more detail while you work on them.

    Back to your question - they are, roughly speaking, equally matched. One won't feel slower than the other. So it comes down to the display - it's just that simple. One has a 5K display, the other one is cheaper for similar performance.
  5. Maric thread starter macrumors newbie

    Dec 13, 2014
    I understand the fact that the retina imac looks very nice. Do you have the baseline model like I mentioned before or a upgraded version? Does it run heavy after effects work very well?
  6. Maric thread starter macrumors newbie

    Dec 13, 2014
    Thanks! Do you think the retina iMac will have a hard time handeling 4K video playback or 4k video playback with slight color correction?

    ( I am planning to downscale my 4k projects to 1080p though so I have much more detail than normal 1080p video while still having 1080p video which I think should make the playback easier as well. )
  7. driftless macrumors 65816


    Sep 2, 2011
    The 5K screen for what you do is a game change.
  8. joema2 macrumors 68000


    Sep 3, 2013
    The non-Retina iMac will work OK; I edit 4k GH4 material on a similar machine now.

    That said GPU is important (but not all-important) so I wouldn't suggest the RiMac with 290X, rather the R295X.

    Another option would be the non-Retina iMac with SSD. If you are doing any significant video editing, that won't fit on the internal drive so you'll have to use external storage. In that case why not use SSD for the internal since it's faster?
  9. Maric thread starter macrumors newbie

    Dec 13, 2014
    Thanks. Do you think having a SSD rather than a fusion drive will incease 4k video playback performance? I have not really tought about that. Would it be best for me to go with a 256gig SSD ( from Apple ) with a external drive from Western Digital or something like that to store all my media? So i gueas a setup like this will give me faster exporting times comparerd to the fusion drive and perhaps faster video playback as well If I'm getting you right?
  10. yjchua95 macrumors 604

    Apr 23, 2011
    GVA, KUL, MEL (current), ZQN
    I advocate a full SSD setup for pure speed and reliability. It's better to have the spinning part break externally than internally.
  11. redheeler macrumors 604


    Oct 17, 2014
    With a 256 GB SSD you'll be able to store twice as much data on the SSD portion, and as already mentioned the external HDD will be easier to replace. Read performance on the 256 GB SSD will only be marginally better, so for playback it won't make much of a difference, but its write performance will be better for copying large files. Of course speeds also depend on the brand of SSD you get in either the Fusion drive or 256 GB SSD.

    Fusion drive is a good option if you're on a budget or must save some money by not paying extra for external USB 3 storage, but otherwise I would fully recommend the 256 GB SSD.
  12. andy9l macrumors 68000

    Aug 31, 2009
    England, UK
    I'm not sure why there has been so much confusion about which setup will offer better performance, but let me clear that up.

    The non-retina iMac setup will offer about a 20% performance boost over the 5K setup. Based on aggregated benchmark results.

    You're a video editor. That means an i7 (ie. Hyper threading) and improved GPU will vastly increase performance for your usage. That's exactly what the non-retina setup offers.

    The 780M outperforms the M290X by a sizeable margin, and we have even seen it outperform the M295X in some arbitrary benchmarks.

    See this graph for a good usage example:


    I would agree with others - make sure you get a SSD if you're comfortable with external storage.
  13. Maric thread starter macrumors newbie

    Dec 13, 2014
    Thanks. That cleans thing up a bit. Do you know where I can find more of those benchmarks regarding After Effects performance between the ( two ) machines? I cant seem to find them anywhere around the web...

    What would you do? Is the 20% performance increase worth the loss of a 5k screen? This is the main question I'm having at the moment. Of course I need to check the screens out side by side in the store but I just don't know if a 12 second export time difference is that noticeable in real life? What do you think? Is the i7 in the NON-retina really that much faster than the i5 in the 5k iMac? They both boost up to 3.9Ghz.

    It's no problem for me configuring both versions with a SSD and getting external USB 3 Storage by the way. That is a very good idea!
  14. andy9l, Feb 22, 2015
    Last edited: Feb 22, 2015

    andy9l macrumors 68000

    Aug 31, 2009
    England, UK
    Sure, here's a couple of sources:


    I should be clear, the 20% boost will not be a consistent 20% - only during certain intensive tasks. But to answer your question about the 3.5GHz i7 vs. the 3.5GHz i5, the i7 will be drastically faster during tasks that allow for multi-threading (ie. exporting/encoding/rendering video in your case), but almost identical for more general single-threaded tasks. You'll need to look at your specific usage to work out how much time you spend on multi-threaded vs. single-threaded tasks.

    i7 processors offer something called hyper-threading. At a basic level, this is virtual simulation of more cores. It will split the physical cores it has, 4 in this case, into '8' virtual cores. I use inverted commas because this is not the same as having an eight-core processor, of course, but it's much faster than the static quad-core of an i5. Again, this will only affect tasks that can be multi-threaded or run in parallel.

    What would I do? Well, that's hard to say since I'm not a video editor and I don't know enough about what a 20% performance boost really means. I can interpret benchmark graphs all day, but I don't know enough about the real-world usage. I don't know what's painful to wait for when editing...

    If it meant 8 hours of exporting instead of 10 hours, I might opt for the non-retina. If it meant 16 minutes instead of 20 minutes...well, I'd probably get the 5K iMac.

    I don't think anyone on here should tell you how to spend your money, though.

    I would also add, even though I returned my 5K iMac due to being disappointed with the GPU performance, the screen is absolutely stunning. So much so that I'm waiting for the next generation 5K iMac rather than buying a Mac Pro with a 4K external. As an all-in-one computer, it's absolutely fantastic. Best-in-class. And that's coming from a guy who was "disappointed".

    Edit: One thing that just came to mind that may seal the deal for you - the 5K iMac CANNOT be used as an external display. Not in 5K, not in 1440p, not in 1080p, not in VGA. You simply cannot use the 5K iMac as an external display. That means that when it gets old and tired in a few years, you're left with a paperweight - not a handy spare 5K screen.
  15. Maric thread starter macrumors newbie

    Dec 13, 2014
    Thank you very much. Your advice helped me out a lot. Now it's time to check the screens out in real life and see the performance of the 5k imac so I can decide which one I'm going to choose. :)

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