iMac 5k 2017 with 4K external displays your experiences

[velocityg4]

I'm just looking for experiences of 5K iMac owners who paired their iMac with 27" 4K external displays.

How does it looK? My concern is 2560x1440 scaling. If the 4K monitors end up looking blurry compared to the built in 5K display. Also if getting scaling to function on the external displays is problematic.

As the system will need to be triple displays. A 5K monitor is not an option. Since the iMac can't run two of them. I know the iMac Pro can. But an iMac Pro with dual external 5k displays, Vega 64, 64GB RAM and 1TB SSD runs about $4,500 more than a 7700K iMac with Radeon 580, 64GB RAM, 1TB SSD and dual decent 4K displays.

If the 4k monitors look horrible with 2560x1440 scaling. How do 2560x1440 displays look when paired with a 5K iMac? Do they look better or worse than 4K?

How well does scaling work? When moving a picture, text, window, &c from the 5K display to others. Is there any jump in size or just fine detail?

I'm just seeing if it is worth nearly twice the price. Just to have two external 5K displays.

 

[theluggage]

How does it looK?

In a dramatic and unexpected turn-out, a 27" '4k' UHD display is not as sharp as a 27" 5k display!

However, in my opinion, Scaled "Looks like 2560x1440" mode on a 4k display looks really good. If you compare it close up with 5k then, yes, it is slightly less crisp. However, it is a completely different ball game to the awful results you usually get when running a display at non-native resolution using the display's own upsampling: As I understand it, the Mac renders the screen at 5k internally, then uses the GPU to downsample to 4k.

(My 4k is a cheap'n'cheerful one, so the colour isn't in the same league as the iMac display, but that's a different issue - but still one that might affect you if you want consistent colour across 3 screens).

How do 2560x1440 displays look when paired with a 5K iMac?

- the same as 1440p displays always looked: really, really good until you spoiled yourself by using a 4k/5k display, after which OMG you can see the pixels, ugh!!!...

Do they look better or worse than 4K?

Definitely worse: remember, on a 4k screen connected to a retina-capable Mac what you're getting in "looks like 2560x1440" mode isn't 2560x1440 upsampled to 4k, but a virtual 5120x2880 screen downsampled to 4k. Unless you're using old, pre-retina software, you get more detail than you would see on a 1440p display.

How well does scaling work? When moving a picture, text, window, &c from the 5K display to others. Is there any jump in size or just fine detail?

My 4k is actually 28" so, with both screens in "looks like 1440p", things render slightly larger than on the iMac screen. I'd expect 27" screens to match more-or-less exactly.

A 5K monitor is not an option. Since the iMac can't run two of them.

Complaints on a postcard to Intel for not supporting DisplayPort 1.4 in their Thunderbolt/USB-C controllers.

(NB: by "4k" above I mean "so-called-4k UHD 3840x2160" of course. )