Another iMac Dilemma

[05JGM]

I am in the market for a new iMac. I need a good Mac to edit family and vacation videos from a GoPro, most of which are shot in 4K, but I am by no means a power user for video editing. It will also be used as a family computer for the normal web browsing, etc. I am after something that will perform well for me when I am using it.

So far I have narrowed it down to 3 options and screen size is not really that big of a factor for me. I am more focused on performance when video editing.

	Option 1	Option 2	Option 3
Display	27 inch Retina 5K	27 inch Retina 5K	21.5 inch Retina 4K
Processor	3.1GHz 6-core 8th-generation Intel Core i5 Turbo Boost up to 4.3GHz	3.0GHz 6-core 8th-generation Intel Core i5 Turbo Boost up to 4.1GHz	3.2GHz 6-core 8th-generation Intel Core i7 Turbo Boost up to 4.6GHz
RAM	8GB 2666MHz DDR4	8GB 2666MHz DDR4	16GB 2666MHz DDR4
GPU	Radeon Pro 575X with 4GB of GDDR5 memory	Radeon Pro 570X with 4GB of GDDR5 memory	Radeon Pro 560X with 4GB of GDDR5 memory
Storage	256GB SSD	256GB SSD	256GB SSD
Cost	$2,099​	$1,899​	$1,999​
OWC RAM	32 GB (16GBx2)	32 GB (16GBx2)
New Cost	$2,239​	$2,039​

My biggest questions are:
1) Is the tradeoff of getting the i7 worth not upgrading the Ram, past 16GB and having a lesser GPU? or Is the i5 sufficient for my needs and having more Ram and a better GPU would be more beneficial?
2) Also, is there any other component or option I am overlooking in my decision and should take in to account?

 

[Successful Sorcerer]

With your use I don't think the more expensive 27 version or going for the i7 in the 21.5 inch is worth it, it might be noticeable but not very much. When editing 4K I really recommend the 27 inch over the 21.5 inch though. It's more fun and easier to check the quality and adjustments you make to the videos. 4K on a 21.5 inch is a bit overkill in my opinion although it'll definitely look good.

Edit: I guess you'll add an external SSD for the video's right? 256gb for 4k material usually isn't enough.

 

[MandiMac]

You definitely want a 27-inch screen for editing of any kind, so the 21.5 inch is nice but out of the question. The i7 advantage is negligible; the 27-inch iMac has better cooling to boot and you want the better GPU, it helps in the long run.

Between option 1 and 2 I think that option 2 is sufficient for your use case, and I would argue that 16 GB RAM are enough.

 

[Ifti]

As mentioned above, take into account an external SSD for editing with. Thunderbolt 3 if you can stretch to it. USB 3.1 Gen 2 if cost is an issue. The Samsung T5 or the Glyph AtomRAID are the ones I generally recommend....
If cost is not an issue then the Thunderblade V4 is what I use and highly recommend!

Also agree with Option 2. Sacrifice some of the RAM and drop down to 16GB if you can't stretch to the external editing drive. If that's not an issue, keep the 32GBm, but definitely get the scratch disk.

 

[J.Gallardo]

A 27" Retina Display is a WONDERFUL monitor. For about the same price, the BIG difference is the display. I've got a 27" iMac, my wife a 21" one. You'll never regret getting this quality big screen and think: "well, 21" could serve the same".
And CPU is not going to be your bottleneck. If you were a "pro", perhaps some more speed could be interesting... but just for repeated, massive and heavy processing duties.
(In fact, I think the display is the only component with a reasonable price/value ratio, given Apple BTO options cost).

 

[colodane]

Definitely go with one of the 27 inch options even if you discount the advantage of the extra screen space. They will be quieter machines than the 21.5 inch i7, and allow you upgrade the RAM affordably.

 

[Fishrrman]

Be aware that if $$$ is consideration, you get "more for your money" by buying from the Apple online refurbished store.

Buy a 27" iMac with 8gb of RAM. Then add more yourself (very easy with the 27" model, NOT SO with the 21").

A 256gb SSD will do.
For much 4k, you might consider 512gb instead.

Again, more for your money at the refurb store.

 

[05JGM]

Thanks for the feedback everyone. Yeah, I am planning on get an external SSD and will look in to the ones Ifti mentioned.

I am not opposed to a refurb, just have to find the right combination.

One last question what is the "bare minimum" GPU I can get away with? Option 2 above has the Radeon Pro 570X but I'm not sure if I found a refurb with a lesser GPU if it would still be ok or if the 570 should be my baseline.

 

[Daniel Marchant]

Thanks for the feedback everyone. Yeah, I am planning on get an external SSD and will look in to the ones Ifti mentioned.

I am not opposed to a refurb, just have to find the right combination.

One last question what is the "bare minimum" GPU I can get away with? Option 2 above has the Radeon Pro 570X but I'm not sure if I found a refurb with a lesser GPU if it would still be ok or if the 570 should be my baseline.

570 is quite ok for normal graphic task like video editing, 575X is just marketing BS, you could barely notice a difference even from 570 to 580. From 570 really the next level is a pro graphics card but we are talking about vega or similar and that is also next level budget.

If you experience any lag editing on you imac on intensive load, lowering you screen resolution will increase performance.

The i5 in this machine is ok for most task and you only can notice a difference when exporting or rendering the video in which i7 is about 24% faster.

 

[satchmo]

I’ve read that increasing your GDDR5 RAM to 8GB vs 4GB also helps. I’m no video expert, so perhaps others can comment on this.