Should I upgrade my late 2015 5k to 2017 model?

[Martynas]

Hello,

I have an iMac 5k MK472 (R9 M390 graphic card, 1TB Fusion drive, 3.2 GHz processor, 8gb Ram). I have a chance to get a new iMac (looking for a model with a 580 graphic card, 3.8GHz i5 and 2TB Fusion, 8gb Ram). I am photographer and also more and more I do some work with FCPX. Does anyone have clue how much improvement would new model bring? For now my drone footage from Phantom 4 PRO (4k, H264) is quite a task for iMac (takes a just bit of time to render, there were few program crashes too after some heavy effects applied). Photoshop runs fast as hell (I can edit even 120 mpx panorama with not a single lag), Lightroom is mixed of bag because of older (5.6) version which does not use GPU (possibly 6.x version would solve everything, I read thath in many forums). I am happy with my computer but as I said earlier, there is a chance to get the new one, just want to know how much new processor and graphic card would affect the speed say in FCPX? Is it miles ahead or just subtle upgrade? Thank you!

 

[Samuelsan2001]

Yeah its a pretty wide margin on benchmarks. The 580 is almost 2x as fast as the 390.

https://www.digitaltrends.com/computing/imac-2017-benchmarks/

 

[joema2]

...I have an iMac 5k MK472 (R9 M390 graphic card, 1TB Fusion drive, 3.2 GHz processor, 8gb Ram). I have a chance to get a new iMac (looking for a model with a 580 graphic card, 3.8GHz i5 and 2TB Fusion, 8gb Ram)....I do some work with FCPX. Does anyone have clue how much improvement would new model bring? For now my drone footage from Phantom 4 PRO (4k, H264) is quite a task for iMac...

I have the top-spec 2015 and 2017 i7 iMac 27. For some things the 2017 only feels modestly faster but when transcoding 4k H264 to proxy in FCPX it is 2x faster. Some GPU-intensive effects are faster, but the biggest improvement is encode/decode speed in FCPX on 4k H264 material. I suspect this is due to improvements in the Kaby Lake Quick Sync logic.

I tested it side-by-side vs a 12-core D700 Mac Pro and the 2017 iMac 27 is considerably faster on most things. It is the only Mac that can edit 4k H264 at halfway decent performance without creating proxies. However if you are doing multicam or a "difficult" version of H264 (such as 10-bit material from a GH5) it still requires proxies for good performance, but it generates them twice as fast as the 2015 model and 3.5x faster than the 12-core Mac Pro.

 

[imac2017mm]

Depends. If we knew for certain that new models were releasing next year... then I would wait.

 

[Martynas]

Thank you for response. I was always curious what is the most important part when working with video or photos? Is it GPU, processor or RAM? I always thought it is GPU but I can be wrong.

 

[Samuelsan2001]

Thank you for response. I was always curious what is the most important part when working with video or photos? Is it GPU, processor or RAM? I always thought it is GPU but I can be wrong.

That depends purely on what you are doing photoshop will cpu bound but video editing is mostly gpu bound. Ram can be very important for loading lots of effects etc. They will all mean something in different scenarios it’s far more complicated than people think, even within the same software different use cases will stress different components.
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Depends. If we knew for certain that new models were releasing next year... then I would wait.

The iMac Pro is releasing in December.

 

[joema2]

Thank you for response. I was always curious what is the most important part when working with video or photos? Is it GPU, processor or RAM? I always thought it is GPU but I can be wrong.

In video editing there is no single answer because each workflow, code path, software and plugin is different. E.g, if your cameras shoot ProRes or DNxHD, the computational burden of editing may be lower, so certain tasks are more I/O intensive. If you apply GPU-intensive effects, then it's a combined GPU and I/O issue. But even for ProRes or DNxHD codecs the CPU burden can be very high and frequent. Anyone can see this themselves by importing or transcoding to those codecs and applying time-consuming effects such as stabilization, Neat Video noise reduction, etc.

However if you shoot and edit h264 or transcode to proxy, then it's clearly a more CPU-bound issue. Anyone can see this themselves -- just watch the CPU graph in Activity Monitor or iStat Menus while importing some H264 content, scrubbing the timeline and exporting to H264. The CPU cores will be very high, especially on Premiere. If CPU cores are all high, then it's not usually GPU-bound or I/O bound. iStat Menus allows direct graphing of GPU activity.

Even for effects, GPU usage can be highly variable. Neat Video noise reduction can be configured to use all CPU, all GPU or a mix of CPU + GPU. Under the plugin's Tools>Preferences>Performance menu, they have a built-in testing tool for determining which mix provides optimal performance on your machine and editing software. In general the fastest Neat Video performance on a Mac using FCPX is a mix of CPU and GPU. But even in the CPU+GPU case it's really using the CPU more, as shown by iStat Menus.

Lightroom has a preference to enable/disable GPU acceleration. However the software is so poorly written that certain tasks such as correction brushes can actually slow down if GPU acceleration is enabled -- even on a pretty fast GPU. This is on a 2017 top-spec iMac 27; maybe it works better on Windows but this is a Mac forum so that's not relevant to the question.

Other effects plugins may claim to heavily use the GPU but they clearly do not, as can be seen from watching Activity Monitor or iStat Menus. Examples include Digital Anarchy's "Flicker Free", a sophisticated de-flickering plugin: https://digitalanarchy.com/Flicker/main.html

Also Imagenomic's Portraiture, the best available skin processing software: http://imagenomic.com/VideoPluginSuite.aspx

Both are excellent plugins that do a miraculous job in their areas, but they are not GPU-bound but rather CPU-bound.

However this isn't saying that GPU is non-important. Developers of editing software are constantly looking for ways to better leverage the GPU, so you want a robust one.

 

[Martynas]

joema2

Wow, amazing and helpful post! Thank you very much! Well, Phantom 4 PRO is able to shoot in H265 but I never tried it. With High Sierra update I might consider to use H265 and see the difference.