2017 iMac for Final Cut Pro X

[JavaBlend]

Hey everyone,

Yesterday I made a thread in the Buying Advice forum, but someone suggested that I should make a thread about this here as well.

Basically, I'm looking to ditch my cheap Windows laptop and indulge myself in the wonderful world of Apple. I've always been a tech enthusiast, and never even considered Apple, until I found out how well-optimized Final Cut Pro X is, even on older / lower-end hardware.

I'm currently working to get a degree in journalism. I've finished my freshman year, and in the second semester of the coming year, I'll specialize in written journalism. For written journalism (which includes basic photo editing in Adobe Lightroom), any old PC will work. But I'm very passionate about storytelling, so I want to continue making videos independent from school. I've decided that I'm probably going to get a Panasonic G7 (which shoots good 4K video), as well as a 2017 27" iMac.

Because I'm a college student, I can get Apple computers at a decent discount. I can get the base model 27" iMac (i5/570, 8GB RAM, 1TB Fusion Drive) for €1,899, the i5/575 model for €2.089, and the i5/580 model for €2,349. All prices are after tax.

However, someone in the previous thread said that I should get the 256GB SSD over a fusion drive, and then edit off of external storage. I think I agree. This bumps the price up quite a bit, though.

In an ideal world, I'd like to get the base i5/570 iMac with an SSD and call it a day. Especially since I'm still a student, and budget definitely is an issue. This is why upgrading to the i7 is basically a no-go for me, unless I REALLY have to.

However, since I'll be doing video editing in 4K (with color grading etc.), I'm not sure if that'll be good enough. Also, while fast render speeds are nice, I'm more concerned about smooth timeline scrubbing/preview playback and applying effects at a decent speed.

TL;DR: I want to know if the base model iMac with SSD will be adequate for 4K video editing in Final Cut Pro X. I'll upgrade the RAM to 24GB myself later down the line, as more money becomes available. If that's not good enough, I'd like to know if the i5/575 (probably without SSD) model will be good enough.

Thanks in advance!

 

[PJivan]

Hey everyone,

Yesterday I made a thread in the Buying Advice forum, but someone suggested that I should make a thread about this here as well.

Basically, I'm looking to ditch my cheap Windows laptop and indulge myself in the wonderful world of Apple. I've always been a tech enthusiast, and never even considered Apple, until I found out how well-optimized Final Cut Pro X is, even on older / lower-end hardware.

I'm currently working to get a degree in journalism. I've finished my freshman year, and in the second semester of the coming year, I'll specialize in written journalism. For written journalism (which includes basic photo editing in Adobe Lightroom), any old PC will work. But I'm very passionate about storytelling, so I want to continue making videos independent from school. I've decided that I'm probably going to get a Panasonic G7 (which shoots good 4K video), as well as a 2017 27" iMac.

Because I'm a college student, I can get Apple computers at a decent discount. I can get the base model 27" iMac (i5/570, 8GB RAM, 1TB Fusion Drive) for €1,899, the i5/575 model for €2.089, and the i5/580 model for €2,349. All prices are after tax.

p.s. with optimise media and 15 minutes editing you can end up at 300GB of Harddrive usage....

However, someone in the previous thread said that I should get the 256GB SSD over a fusion drive, and then edit off of external storage. I think I agree. This bumps the price up quite a bit, though.

In an ideal world, I'd like to get the base i5/570 iMac with an SSD and call it a day. Especially since I'm still a student, and budget definitely is an issue. This is why upgrading to the i7 is basically a no-go for me, unless I REALLY have to.

However, since I'll be doing video editing in 4K (with color grading etc.), I'm not sure if that'll be good enough. Also, while fast render speeds are nice, I'm more concerned about smooth timeline scrubbing/preview playback and applying effects at a decent speed.

TL;DR: I want to know if the base model iMac with SSD will be adequate for 4K video editing in Final Cut Pro X. I'll upgrade the RAM to 24GB myself later down the line, as more money becomes available. If that's not good enough, I'd like to know if the i5/575 (probably without SSD) model will be good enough.

Thanks in advance!

I'dd go for the base 580 model as FCP X use OpenCL/metal and it's greatly optimised for GPU computing....
256gb is just way to small for video editing so you would use an external HD anyway.....at this stage take the base Fusion drive and you can alway buy an external ssd later on....
also to be fair HDD don't do that much of a difference in rendering speed.

I did a 15minutes 4k edit yesterday and the brand new library was 320gb big....using optimised media

 

[JavaBlend]

I'dd go for the base 580 model as FCP X use OpenCL/metal and it's greatly optimised for GPU computing....
256gb is just way to small for video editing so you would use an external HD anyway.....at this stage take the base Fusion drive and you can alway buy an external ssd later on....
also to be fair HDD don't do that much of a difference in rendering speed.

I did a 15minutes 4k edit yesterday and the brand new library was 320gb big....using optimised media

Hi PJivan, Thanks a lot for the reply.

I've been considering the 580 model too, but it's kinda pushing my budget. Of course, if the difference in performance is that big over the 575, I'd be willing to go for it.

I agree with you that 256GB is too small for video editing. That being said, I do already own a 1TB external HDD, and I've seen a lot of great deals on 3TB ones for under €100. I could just sticky tape it to the back of the machine and never worry about it. I'd just put the OS + FCPX on the SSD, and edit from the external storage.

My main concern is that I've heard some people complaining that fusion storage apparently slows down over time. Of course, I'm still very open to all options. I'm in no hurry whatsoever. I might even wait for the back to school sale to start in a bit.

I'm still kind of considering going with the i5/575 model. Not sure if I'll add the SSD (budget is a struggle). Though even with the SSD, it would still be more affordable than the base 580 model. Will the 575 still be good enough in terms of editing? Again, I really prefer smooth editing over render times. I tend to walk away and do other stuff while I'm rendering, anyway.

 

[PJivan]

Hi PJivan, Thanks a lot for the reply.

I've been considering the 580 model too, but it's kinda pushing my budget. Of course, if the difference in performance is that big over the 575, I'd be willing to go for it.

I agree with you that 256GB is too small for video editing. That being said, I do already own a 1TB external HDD, and I've seen a lot of great deals on 3TB ones for under €100. I could just sticky tape it to the back of the machine and never worry about it. I'd just put the OS + FCPX on the SSD, and edit from the external storage.

My main concern is that I've heard some people complaining that fusion storage apparently slows down over time. Of course, I'm still very open to all options. I'm in no hurry whatsoever. I might even wait for the back to school sale to start in a bit.

I'm still kind of considering going with the i5/575 model. Not sure if I'll add the SSD (budget is a struggle). Though even with the SSD, it would still be more affordable than the base 580 model. Will the 575 still be good enough in terms of editing? Again, I really prefer smooth editing over render times. I tend to walk away and do other stuff while I'm rendering, anyway.

Off course is enough, all I'm saying is that storage will be repleceable especially once thunderbolt license will be free next year I'm sure we will se an increasing number of m.2 to thunderbolt with trim support an all, while you will never be able to upgrade gpu....

I own full ssd mac and fusion drive one...to be fair while the 1tb version with 32 is just not enough the 2tb with 128gb it's quite a nice balance and work very well...all your os and software will be running on ssd...also high sierra will increase FD efficiency, I don't get the FD hate...off course 2tb ssd is better but I would rather have a 2TB FD than a 256GB SSD

 

[gian8989]

Go with 512 ssd. You will regret fusion drive.

i5 will be slower but i would sacrifice the i7 to get an ssd.

All gpu of 2017 imac are faster than best gpu of 2015 imac.

If you want you can save fcpx money and use it on ssd and use davinci free version than is now optimize on mac and amd card.

Video: Fcpx vs davinci vs premierpro

 

[AZhappyjack]

Hi PJivan, Thanks a lot for the reply.

I've been considering the 580 model too, but it's kinda pushing my budget. Of course, if the difference in performance is that big over the 575, I'd be willing to go for it.

I agree with you that 256GB is too small for video editing. That being said, I do already own a 1TB external HDD, and I've seen a lot of great deals on 3TB ones for under €100. I could just sticky tape it to the back of the machine and never worry about it. I'd just put the OS + FCPX on the SSD, and edit from the external storage.

My main concern is that I've heard some people complaining that fusion storage apparently slows down over time. Of course, I'm still very open to all options. I'm in no hurry whatsoever. I might even wait for the back to school sale to start in a bit.

I'm still kind of considering going with the i5/575 model. Not sure if I'll add the SSD (budget is a struggle). Though even with the SSD, it would still be more affordable than the base 580 model. Will the 575 still be good enough in terms of editing? Again, I really prefer smooth editing over render times. I tend to walk away and do other stuff while I'm rendering, anyway.

I'm using a 2015 5K iMac for FCPX, and (Radeon R9 390 video card)... FCPX was not "in the mix" when I got the iMac or I would have gone with the 395X video card... but the real issue is the Fusion drive - especially the 1TB version... the SSD portion is only 24GB, so it's not much better than the 1TB spinner... If you're going with a Fusion drive, I'd strongly suggest going with the 2TB version... or popping for at least 512GB of SSD. Another option would be to go with the 256GB SSD and a TB3 external SSD as your work/scratch drive.

 

[JavaBlend]

Thanks for all the replies everyone!

The 512GB SSD is definitely out of my budget, unless I get the 570 model. That leaves the i5/575 model with 256GB SSD, or the i5/580 model with 2TB fusion drive, which is slightly more expensive. It seems like that might actually be a better deal.

I also read that you can split the 128GB SSD and the 2TB HDD, so that might actually be a great option. 128GB should be enough for the OS + all applications, and 2TB is more than enough for a few 4K projects and school docs.

I've heard about Resolve, too. I'll definitely give that a go, especially for colour grading!

 

[bopajuice]

Hi PJivan, Thanks a lot for the reply.

I've been considering the 580 model too, but it's kinda pushing my budget. Of course, if the difference in performance is that big over the 575, I'd be willing to go for it.

I agree with you that 256GB is too small for video editing. That being said, I do already own a 1TB external HDD, and I've seen a lot of great deals on 3TB ones for under €100. I could just sticky tape it to the back of the machine and never worry about it. I'd just put the OS + FCPX on the SSD, and edit from the external storage.

My main concern is that I've heard some people complaining that fusion storage apparently slows down over time. Of course, I'm still very open to all options. I'm in no hurry whatsoever. I might even wait for the back to school sale to start in a bit.

I'm still kind of considering going with the i5/575 model. Not sure if I'll add the SSD (budget is a struggle). Though even with the SSD, it would still be more affordable than the base 580 model. Will the 575 still be good enough in terms of editing? Again, I really prefer smooth editing over render times. I tend to walk away and do other stuff while I'm rendering, anyway.

I'd go the ssd iMac with an external drive route as well. A mac with an ssd just runs so much better. But one thing to consider is the external drive interface. The ultimate would be an external drive that uses thunderbolt 3.

 

[gian8989]

Thanks for all the replies everyone!

The 512GB SSD is definitely out of my budget, unless I get the 570 model. That leaves the i5/575 model with 256GB SSD, or the i5/580 model with 2TB fusion drive, which is slightly more expensive. It seems like that might actually be a better deal.

I also read that you can split the 128GB SSD and the 2TB HDD, so that might actually be a great option. 128GB should be enough for the OS + all applications, and 2TB is more than enough for a few 4K projects and school docs.

I've heard about Resolve, too. I'll definitely give that a go, especially for colour grading!

If you have no alternative to fusion drive, don't split it. It would get way too slow to work on it.
[doublepost=1499110141][/doublepost]

I'd go the ssd iMac with an external drive route as well. A mac with an ssd just runs so much better. But one thing to consider is the external drive interface. The ultimate would be an external drive that uses thunderbolt 3.

With high sierra and APFS file system ssd will get even more benefit.

 

[JavaBlend]

So the i5/575 model with SSD would be a better choice than the 580 model with 2TB fusion drive then? Would the radeon pro 575 handle 4K editing good enough? I did read that even the base model 570 performs slightly better than the R9 m395x, so it should be fine, but just checking.

It's a shame you can't get the 580 with 256GB SSD.

EDIT: now that I'm thinking about it: would the 570 be adequate too? I don't mind getting the 575, but if the 570 can do it without lag I'd rather save the money

 

[PJivan]

Thanks for all the replies everyone!

The 512GB SSD is definitely out of my budget, unless I get the 570 model. That leaves the i5/575 model with 256GB SSD, or the i5/580 model with 2TB fusion drive, which is slightly more expensive. It seems like that might actually be a better deal.

I also read that you can split the 128GB SSD and the 2TB HDD, so that might actually be a great option. 128GB should be enough for the OS + all applications, and 2TB is more than enough for a few 4K projects and school docs.

I've heard about Resolve, too. I'll definitely give that a go, especially for colour grading!

I'm confused why split...if you have less then 128gb of data then everything would be on ssd....when you go over that then old or leas used files will be copied on hdd..APFS should be able to be much more efficient doing it by sector and recognising file table and storing all the index on SSD
If the plan is to store the media on external mechanical drive why just not let FD do that....

575 and 580 are both capable I'm not saying you can't edit with 575 but I really don't understand the logic...but yes you can destroy the FD and it will be simply a mac with two different HD and you will have to manually manage the data

 

[martinX]

Things I have known for a long time or have recently worked out:

• GPU is the most important factor for rendering on the timeline and exporting, as well as the amount of RAM on the card. Check the BruceX benchmarks. The best card with 8GB of VRAM is a good thing, especially if it's trying to push pixels to a 5k screen at the same time as rendering.
• FCP X eats RAM. Order the iMac with 8GB and buy another 32 (2 x 16GB sticks) from Mac Sales or someone.
• HDD v SSD is not important for FCPX if you are editing on an external drive system.
• SSD is cool and zippy, but not that important for editing.
• I wouldn't get an iMac with less than 1 TB storage. Think about all the stuff you are going to store on it: iTunes library, photo library, movies, documents for years. The iMac I'm using in my main office that I use everyday has a 3TB SSD and it's half full. One in another office has a 1 TB SSD (OMG it's quick) but is only used every now and then and has practically nothing stored internally except for apps. Your main iMac will fill up.
• CPU speed is important for scrubbing along the timeline. i5 versus i7, not so sure. Some say save your money.
• The i7's hyper threading is great for Handbrake's ripping into MP4.
• Exporting from FCPX to MP4 uses Intel's QuickSync on the CPU if you use a single pass setting.
• A RAID5 external drive like the Promise Pegasus is a good solid system with decent speed. Pricey, but good.

 

[cynics]

Go with 512 ssd. You will regret fusion drive.

i5 will be slower but i would sacrifice the i7 to get an ssd.

All gpu of 2017 imac are faster than best gpu of 2015 imac.

If you want you can save fcpx money and use it on ssd and use davinci free version than is now optimize on mac and amd card.

Video: Fcpx vs davinci vs premierpro

I'd be curious to see how well that scales to the 570 and 575 though. Its definitely worth the OPs time to try the free version give it a shot though. I'm actually going to try something similar on my 2013 iMac to see the performance difference between the 2 on "less optimal" hardware.

 

[JVNeumann]

4K editing isn't something that can be done on the cheap without trade-offs, so it might be wise to resign yourself to occasionally choppy scrubbing and having to be economical with your buffering. They're not hard ceilings, they're just things you have to work around and be prepared to wait for.

I'd say the biggest practical issue is probably going to be storage space. You should work from the SSD whenever possible, and move all inactive files to an external.

 

[vapourtrails]

You will always get the same answer on threads like this. The iMac has been able to edit video for quite some time but as soon as a new model comes out the old ones are barely functional and nothing but the new top end model will suffice for editing. Get whichever ever model you can afford and you will be fine.

 

[jclardy]

I went with the 580 and 2TB Fusion, upgraded to 24GB RAM. Running FCPX super smooth with footage from my GH4.

 

[EugW]

I'm not a video guy, but FWIW, the 570 is faster than the M395X (which was the absolute fastest GPU in iMacs last time around), at least in some benchmarks.

http://geekbench.com/blog/2017/06/imac-27-inch-performance-june-2017/

Those are compute benchmarks. Below are 580 benchmarks vs the M395X:

http://barefeats.com/imac580.html

So, even if the 580 were somewhere in the ballpark of 50% faster than the 570, that 570 GPU's performance will rival or even beat the fastest iMac GPU of 2015.

But then again, maybe you should get something faster and with more RAM.

 

[diabora]

Hi JavaBlend,

Up until last week I was editing 4K footage on an rMBP mid 2012. I own and run a one man band video production firm making a decent living from it. With that in mind any new iMac will be able to edit the 4k files from a Panasonic G7. My rMPB handled 4K files from a GH4 OK (FCPX from internal SSD, videofiles on external USB 3 SSD), however the XF AVC 10bit 4K files from my C300 MKII brought everything to a halt.

Originally I wanted a new MBP but the performance of the new 2017 iMac, made me go for that instead. I went with a i7, 580, 1TB, 8 GB (self upgraded to 32GB Cosair vengeance) + a Sandisk extreme 900 1,92 TB external usb-c drive. It´s a great machine no doubt, but I have to admit that I'm a bit underwhelmed with the performance gain over the 5 year old rMBP. I still have to wait for rendering every now and then.

Anyway best advice, buy the best you can afford right now! Stop spending your time wondering 570 vs 575, i5 vs i7 etc. Your time is way better spend learning how to shoot, edit, grade, writing down your original ideas, or just having fun.

PS, go for internal SSD instead of Fusion, the sound of a spinning drive is just plain annoying. If you need more space for editing get external SSD drives. Keep your back-up video files on a WD MyCloud mirror or similar (let it stay in a seperate room, or only connect when needed. always back-up on two drives )

Cheers

/Alex

 

[joema2]

I'm probably going to get a Panasonic G7....I want to know if the base model iMac with SSD will be adequate for 4K video editing in Final Cut Pro X....I'm more concerned about smooth timeline scrubbing/preview

If you mean editing camera-native 4k H264, virtually no computer or editing software is fast to smoothly edit large amounts of 4k H264. This includes the 12-core Mac Pro with dual D700 GPUs and with media on a Thunderbolt 2 SSD RAID (which I tested last week).

This is mainly a CPU limitation, not a GPU or I/O limit. It's caused by the very compute-intensive nature of rapidly decoding H264. The only way to dramatically speed that up is using Intel's Quick Sync, which FCPX already does on i5 and i7, but not Xeon. To my knowledge Premiere does not use Quick Sync on Mac so is even slower.

However if you transcode that to proxy, almost any computer or editing software is fast enough. Both FCPX and Premiere are both lighting fast on a MacBook Air if editing 4k via proxy. The issue then becomes accepting that proxy transcoding is required and providing the space for this, which is typically about 1.6x the original media size.

I own and have tested side-by-side similar iMac 27s with 3TB Fusion Drive and SSD. For video editing with media on an external drive, there's little performance difference. If you place media on the boot drive SSD is fast enough but not big enough to hold much 4k material. Fusion Drive is big enough but probably not fast enough as it fills up. Thus you often end up using external storage in either case.

For low end truly recreational use, you can put media on the Fusion Drive and it works OK. For anything above that I'd suggest using an external drive, and not a slow one.

I marginally prefer SSD due to the possible better reliability and slightly faster real world performance in a few areas, but in most video editing with media on an external drive it won't make a noticeable difference. However I would not get the 1TB Fusion Drive, either the 2TB or 512GB SSD which is $100 more.

 

[JavaBlend]

Thanks again for all the replies everyone.

As far as transcoding footage goes, I am planning to use either optimized- or proxy media. For now, video editing will be mostly recreational. Maybe I'll start a YouTube channel, but I'll probably just end up making videos for fun, rather than for publishing.

I'm still not completely sure which model I'll get, either the i5/570 with SSD, the i5/575 model with SSD, or the i5/580 model with fusion drive. But I do know now that it probably doesn't matter as much as I anticipated, especially after seeing the benchmarks EugW posted, so I'll just have to see for myself when the time comes to make the purchase.

As far as splitting the fusion drive goes, I just thought the SSD part would simply work as a caching drive, like Intel's new Optane technology. But having the most used files on the SSD seems a lot more useful.

Again, thanks a lot for the help everyone!

 

[EugW]

I have now had a chance to play with the i5-7600. I used to have an i7-7700K. Again, I'm not a video guy, but nonetheless, this may be relevant:

Most of the time the 7700K was silent, with light usage like mail, office applications, light video editing, surfing, h.264 video playback. No problem there. But as soon as I started taxing the CPU, the fan would ramp up and it would become quite noticeable. And if I exported a video using Handbrake, the fan would quickly hit maximum temperatures, and the fan would go to max 2700 rpm. I didn't do that often, but when I did, it was annoying.

OTOH, the 7600 stays quiet all the time. I ran some benchmarks to peg all four cores at 100% usage, and even then the chip stayed relatively cool, and the fan speed never budged from its base 1200 rpm speed. After about 10 minutes of video encoding in Handbrake again with the CPU load at 100%, temps did climb from the 60s to the low 80s, but it still wasn't enough to trigger the fan to speed up. I didn't bother continuing the test after this, because this is all I need. I'm not sure if the fan would have ever sped up or if the temps would have just leveled off in the 80s, but either way, that's fine with me. I can deal with the fan becoming audible with moderate speeds after 15 minutes of hard number crunching, but the 7700K's propensity to go to max 2700 rpm even after well under a minute of heavy use was annoying enough to get me to return it.

Your mileage and needs may vary of course, but the i5-7600 may present a decent middle ground. Acceptable CPU speeds in a quiet package, but with a decent GPU in the Radeon Pro 575, which is good jump in speed over the 570 that comes with the i5-7500.

 

[gian8989]

Thanks again for all the replies everyone.

As far as transcoding footage goes, I am planning to use either optimized- or proxy media. For now, video editing will be mostly recreational. Maybe I'll start a YouTube channel, but I'll probably just end up making videos for fun, rather than for publishing.

I'm still not completely sure which model I'll get, either the i5/570 with SSD, the i5/575 model with SSD, or the i5/580 model with fusion drive. But I do know now that it probably doesn't matter as much as I anticipated, especially after seeing the benchmarks EugW posted, so I'll just have to see for myself when the time comes to make the purchase.

As far as splitting the fusion drive goes, I just thought the SSD part would simply work as a caching drive, like Intel's new Optane technology. But having the most used files on the SSD seems a lot more useful.

Again, thanks a lot for the help everyone!

Just my opinion but even 3tb fusion drive is not that big of a storage and you will eventually need another external hdd (if not for storage for backup). This new iMac has thunderbolt 3 so in 1-2 years we should see fast external 2tb ssd at decent price and at the same time you would have a fast internal ssd without the hdd noise and slowdown.

 

[Magus90]

Thanks again for all the replies everyone.

As far as transcoding footage goes, I am planning to use either optimized- or proxy media. For now, video editing will be mostly recreational. Maybe I'll start a YouTube channel, but I'll probably just end up making videos for fun, rather than for publishing.

I'm still not completely sure which model I'll get, either the i5/570 with SSD, the i5/575 model with SSD, or the i5/580 model with fusion drive. But I do know now that it probably doesn't matter as much as I anticipated, especially after seeing the benchmarks EugW posted, so I'll just have to see for myself when the time comes to make the purchase.

As far as splitting the fusion drive goes, I just thought the SSD part would simply work as a caching drive, like Intel's new Optane technology. But having the most used files on the SSD seems a lot more useful.

Again, thanks a lot for the help everyone!

Hey There,

I am going through the same choice now and was wondering which you chose and how you made out?

I actually have an unopened I5 570 4gb sitting here. But was wondering if i should return it and get either I5 575 4gb for $200 more. Or get the I7 575 4gb for $400 more. In all 3 configs i have a 256 SSD in there. I have 7 more days to return it.

I will be doing editing in only 1080p 60fps, no 4k or anything. But it would be nice to have the option in case i do.

Is it worth upgrading, or just keeping what i have??

Thanks so much

 

[nilk]

I don't know the answer here, but I am planning to eventually edit 4k with my base model 27" iMac (i5/570, 512GB SSD) and don't see why it couldn't handle 4k editing smoothly considering you can always edit with proxies.

Of course this is just personal home video stuff at the moment, and I'm never on a deadline. If something is going to take some time to complete, it doesn't matter if it completes 30% or even 50% faster, as I'm usually walking away or working on something else for a while. I usually start an export of my project at the end of the night and go to bed without waiting for it to complete.

If I ever feel the limitations of the 570, I can get an eGPU which High Sierra will support. I'd rather put money into external gear that I can take with me to my next machine (waiting for the next-gen Mac Pro). The exception is that I think a pure SSD is worth the cost, even if it's just a 256GB that only fits your OS/apps and you have everything else external. The 1TB Fusion with it's 24GB SSD seems like a bad choice to me.

I also value low noise / heat / power usage, which is an area I'm guessing the i5/570 has an advantage in (would like to see these things measured, though). Personally I think the base model 27" i5/570 is the best value of all current Mac desktop machines. And of course buy 3rd party RAM with any of the 27" models to save quite a bit (in my case I bought 2x16GB for a total of 40GB RAM).

 

[EugW]

I don't know the answer here, but I am planning to eventually edit 4k with my base model 27" iMac (i5/570, 512GB SSD) and don't see why it couldn't handle 4k editing smoothly considering you can always edit with proxies.

Of course this is just personal home video stuff at the moment, and I'm never on a deadline. If something is going to take some time to complete, it doesn't matter if it completes 30% or even 50% faster, as I'm usually walking away or working on something else for a while. I usually start an export of my project at the end of the night and go to bed without waiting for it to complete.

If I ever feel the limitations of the 570, I can get an eGPU which High Sierra will support. I'd rather put money into external gear that I can take with me to my next machine (waiting for the next-gen Mac Pro). The exception is that I think a pure SSD is worth the cost, even if it's just a 256GB that only fits your OS/apps and you have everything else external. The 1TB Fusion with it's 24GB SSD seems like a bad choice to me.

I also value low noise / heat / power usage, which is an area I'm guessing the i5/570 has an advantage in (would like to see these things measured, though). Personally I think the base model 27" i5/570 is the best value of all current Mac desktop machines. And of course buy 3rd party RAM with any of the 27" models to save quite a bit (in my case I bought 2x16GB for a total of 40GB RAM).

Not that I disagree with your post in general, but an eGPU doesn't usually work with the internal display.

OTOH, the 570 is at least as fast as the fastest GPU for the 2015 iMacs, so it's no slouch.