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Black Diesel

macrumors 6502
Original poster
Mar 15, 2011
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I'm getting ready to upgrade my old 27" iMac and would like a triple display setup. The iMac 5K in the middle with a 5K monitor on each side. After some quick searching it looks like apple has yet to release a standalone 27" 4k or 5k apple cinema display? That's a shame...seems like they would sell a ton of them to people like me who can't live with less than 3 displays...

Do any of you have a 5K iMac with 2 additional displays? If yes, what are you using and how do they work with the iMac?
 
There are limitation on what the iMac can drive.

https://support.apple.com/en-us/HT206587

In short the iMac with the M395X can drive two external 4K displays, or 1 external 5K display (connected with two cables).

All other iMacs can drive a single external 4K display, or two non-4K displays.

So if this is something you really want, you need to upgrade to the M395X (and I would suggest waiting until the expected October updates come out, because they will feature improved graphics cards). Rumor has it the October release will also feature an Apple external 5K thunderbolt display, but my guess is the iMac will still only be able to drive one of them.

If it were me, I'd wait and get the iMac released in October with the best graphics card option then get two Dell P2715Q displays to go with it (Those are 27" IPS+LED+SST displays, but they are 4K instead of 5K so they won't be a perfect match) you are likely to get two of those for the price of single Apple 5K Thunderbolt Display. Though two matching 5K displays might actually be nicer than a 4K(UHD)+5K+4K(UHD) setup.

I don't think you will be able to drive two external 5K displays with an iMac unless Apple surprises everyone and releases an iMac with dual high end graphics cards. Remember a single 5K display has almost as many pixels as two 4K UHD displays.
 
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There are limitation on what the iMac can drive.

https://support.apple.com/en-us/HT206587

In short the iMac with the M395X can drive two external 4K displays, or 1 external 5K display (connected with two cables).

All other iMacs can drive a single external 4K display, or two non-4K displays.

So if this is something you really want, you need to upgrade to the M395X (and I would suggest waiting until the expected October updates come out, because they will feature improved graphics cards). Rumor has it the October release will also feature an Apple external 5K thunderbolt display, but my guess is the iMac will still only be able to drive one of them.

If it were me, I'd wait and get the iMac released in October with the best graphics card option then get two Dell P2715Q displays to go with it (Those are 27" IPS+LED+SST displays, but they are 4K instead of 5K so they won't be a perfect match) you are likely to get two of those for the price of single Apple 5K Thunderbolt Display. Though two matching 5K displays might actually be nicer than a 4K(UHD)+5K+4K(UHD) setup.

I don't think you will be able to drive two external 5K displays with an iMac unless Apple surprises everyone and releases an iMac with dual high end graphics cards. Remember a single 5K display has almost as many pixels as two 4K UHD displays.


Thanks for the information. It sounds like I will do what you suggested and go with (2) 4K displays such as the Dell you recommended. Is there an issue with having a 5k display in the middle paired with 4K displays on each side? How does that affect my "extended desktop" view? Will fonts and photos look larger on the 4K monitors due to less resolution?
 
Thanks for the information. It sounds like I will do what you suggested and go with (2) 4K displays such as the Dell you recommended. Is there an issue with having a 5k display in the middle paired with 4K displays on each side? How does that affect my "extended desktop" view? Will fonts and photos look larger on the 4K monitors due to less resolution?
Yes they will look different. Things will scale differently as you move them between the screens. There will also be color variations, and lighting/reflection variations. Which is why I say 2 5K displays may actually be a better experience.
 
Yes they will look different. Things will scale differently as you move them between the screens. There will also be color variations, and lighting/reflection variations. Which is why I say 2 5K displays may actually be a better experience.
Ouch, that's a bummer. So is there a way to downrez the 5K iMac to 4K so they all match or is that just plain idiotic? I'm sure 4K looks much better than my old 1080 monitor...
 
Ouch, that's a bummer. So is there a way to downrez the 5K iMac to 4K so they all match or is that just plain idiotic? I'm sure 4K looks much better than my old 1080 monitor...
I think it will look worse than the 4K native displays if you do that. Displays always look best at their native resolution.

If you want 3 matching 4K displays a Mac Pro would work, you may get lucky and Apple will finally update it this year...
 
I think it will look worse than the 4K native displays if you do that. Displays always look best at their native resolution.

If you want 3 matching 4K displays a Mac Pro would work, you may get lucky and Apple will finally update it this year...

Okay, I'll wait until the end of the year to see if they release any new displays. You would think by now they would have some nice standalone 4K displays that can be powered by an iMac in the middle. Thanks for the info
 
I have a 4K monitor and a 1440p monitor on a nMP, both 27" Dell monitors. They both are configured to view at 1440p, with scaling on the 4K monitor. Apart from the extra sharpness on the 4K screen there's little to choose between them and it works fine. When moving windows between different screens an out line is moved to get around the window looking weird (as it does on Windows 10) when moving between monitors with different resolutions.

If I were in your position and was wanting a 3 monitor setup with an iMac then get 2 x 4K screens and you won't notice much difference between 4k and 5K, but they will both run okay along with the internal monitor. Have a look at the Dell P2715Q. It's good value for money and has good colour accuracy for the price. Obviously 4K Eizo screens will be better, but they are almost 6 times the price.
 
I think it will look worse than the 4K native displays if you do that. Displays always look best at their native resolution.

If you want 3 matching 4K displays a Mac Pro would work, you may get lucky and Apple will finally update it this year...
I haven't tried on mine but couldn't the external 4K be set to the same scaled resolution as the 5K? The 5K out of the box is scaled for 1440P. If a 4K is scaled the same I don't think the difference would be that bad.

the color variance will happen no matter what without calibrating each of them even if both monitors are the same brand.

one thing to keep in mind is the color range. You will want to find a monitor with the same color range as the imac.
 
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A 5K iMac isn't much more expensive than a 5K monitor. How about getting 3 iMacs and using some software to make them work together? This also gives the advantage of more computing power.

I have heard of multiple software options such as ShareMouse, Synergy, and Teleport. I haven't tried them, and there may be other options. It is probably worth investigating.
 
A 5K iMac isn't much more expensive than a 5K monitor. How about getting 3 iMacs and using some software to make them work together? This also gives the advantage of more computing power.

I have heard of multiple software options such as ShareMouse, Synergy, and Teleport. I haven't tried them, and there may be other options. It is probably worth investigating.
Ive used Synergy for a little while before. It worked ok. Ultimately didn't like the setup though because often one app would need 2-3 screens of windows. Works fine if you want separate applications per monitor/computer.

A perfect example is Xquartz. I often have 15-20 xwindows open to different machines and applications, but those would all be restricted to whatever machine they were launched on. Just becam to cumbersome.
 
Rumor has it the October release will also feature an Apple external 5K thunderbolt display, but my guess is the iMac will still only be able to drive one of them.

If the next iMac refresh has ThunderBolt 3, it will be able to drive a 5K display over a single TB3 cable (provided the 5K display itself has TB3). If Apple releases a 5K display, I would expect it to be TB3. So a TB3 iMac should be able to drive two 5K TB3 displays (provided the GPU has the horsepower and the new AMD Polaris GPUs expected in the next iMac refresh hopefully will).
 
If the next iMac refresh has ThunderBolt 3, it will be able to drive a 5K display over a single TB3 cable (provided the 5K display itself has TB3). If Apple releases a 5K display, I would expect it to be TB3. So a TB3 iMac should be able to drive two 5K TB3 displays (provided the GPU has the horsepower and the new AMD Polaris GPUs expected in the next iMac refresh hopefully will).
Don't confuse ports with buses. The iMac has two TB ports on a single bus, which means it will only support two display port channels total.

thunderbolt-bus-png.579492

Image taken from other thread...

https://forums.macrumors.com/threads/5k-imac-thunderbolt-ports.1912874/

I could see Apple adding a second bus to a potential iMac Pro, but I think to do it they would need a second video card for the DP channels like the Mac Pro.
 
Don't confuse ports with buses. The iMac has two TB ports on a single bus, which means it will only support two display port channels total.

TB3 supports two DP 1.2 channels over a single port (versus a single DP channel per port in TB1/TB2) so even with a single TB3 bus supporting two ports, it should be capable of handling two 5K displays (GPU willing).
 
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I hope everyone won't mind if a sorta hijack this thread. I have a similar iMac 5k, but only want to add one external and I'm having trouble getting solid answers as far as scaling and sleep recovery for external monitors.

My iMac's specs are:

Late 2015
3.2 i5
32GB RAM (Crucial upgrade)
Radeon R9 M390 (2GB)

I do not do photo or video editing. Since I just need extra workspace for text/'net work I thought I could just throw a cheap 4K monitor on here and be fine, but have learned a lot in regards to cable issues and usability issues as far as the tiny text and GUI elements on the 4K screen.

I bought and returned a refurb AOC 4K unit after being unsatisfied with the general quality, but was also surprised by the almost unusable text size. Then I learned about scaling.

I have also read horror stories about monitors not waking up properly and resizing everything every time they wake up.

I'd like to find a 4K (or possibly 5K) external monitor that will "play" well with my iMac 5K. I won't be so brash as to say money is no object, but I'm not afraid to pay for the right technology. Although, I have read that for my purposes (text and spreadsheet work), I might actually be better off with a QHD 27" unit like the DELL U2715H.

Just looking for some knowledge and advice...

Thanks,

Chris
 
No worries Chris, I'm sure there are a lot of people in the same boat as you. It's pretty sad there's not really a good solution for a triple display 5k/4k iMac config. Will a Mac Pro power (3) 27" 4K monitors without any issues? I may have to look into the Mac Pro if this is my only option.
 
I'm getting ready to upgrade my old 27" iMac and would like a triple display setup. The iMac 5K in the middle with a 5K monitor on each side. After some quick searching it looks like apple has yet to release a standalone 27" 4k or 5k apple cinema display? That's a shame...seems like they would sell a ton of them to people like me who can't live with less than 3 displays...

Do any of you have a 5K iMac with 2 additional displays? If yes, what are you using and how do they work with the iMac?
I am running a 2014 5K iMac with 2 4K Screens off of the ThunderBolt ports.

The only problem I have is with X-Plane, which the graphics can't handle at full resolution, due to the amount of data being moved around. I use 2K on the three screens, and the window covers approximately 60% of the two 4K monitors, and 100% of the 5K one (at 2K).

My 5K iMac is maxed out on everything but memory. I have 24GB on it, instead of 32.

For the 4K screens, I went with the cheapest ones I could find, and got them on sale/return pile at Sears (of all places). $89 for one, and $189 for the other. So far, after 6 months, the only issue I had was the monitors go to sleep too quickly (like 10 seconds, whether you're pressing the menu buttons or not... bizarre.). And yes, they run at 60Hz.
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No worries Chris, I'm sure there are a lot of people in the same boat as you. It's pretty sad there's not really a good solution for a triple display 5k/4k iMac config. Will a Mac Pro power (3) 27" 4K monitors without any issues? I may have to look into the Mac Pro if this is my only option.
Yes, it will. So will an iMac, with a built in 5K display. When I get home, I'll post some pictures to prove it's possible, or a video may be the trick.
 
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I hope everyone won't mind if a sorta hijack this thread. I have a similar iMac 5k, but only want to add one external and I'm having trouble getting solid answers as far as scaling and sleep recovery for external monitors.

My iMac's specs are:

Late 2015
3.2 i5
32GB RAM (Crucial upgrade)
Radeon R9 M390 (2GB)

I do not do photo or video editing. Since I just need extra workspace for text/'net work I thought I could just throw a cheap 4K monitor on here and be fine, but have learned a lot in regards to cable issues and usability issues as far as the tiny text and GUI elements on the 4K screen.

I bought and returned a refurb AOC 4K unit after being unsatisfied with the general quality, but was also surprised by the almost unusable text size. Then I learned about scaling.

I have also read horror stories about monitors not waking up properly and resizing everything every time they wake up.

I'd like to find a 4K (or possibly 5K) external monitor that will "play" well with my iMac 5K. I won't be so brash as to say money is no object, but I'm not afraid to pay for the right technology. Although, I have read that for my purposes (text and spreadsheet work), I might actually be better off with a QHD 27" unit like the DELL U2715H.

Just looking for some knowledge and advice...

Thanks,

Chris
The recommendation of just getting a quality QHD display like the Dell is a pretty good one. The nice thing about a 5K display is that it is essentially a pixel doubled QHD display. This means that is scales both cleanly and easily. If you are currently using your 5K display scaled to QHD (Best setting in display preferences) then a QHD monitor like the U2715H or the discontinued thunderbolt display will have everything scaled to match perfectly. Though it clearly won't have the sharpness and detail of the 5K...

Or you could wait and see if the new TB display that is rumored to be released could be driven by your current iMac with a dual connector adapter of some kind (2x TB2 on one end, 1x TB3 Female on the other). The Dell 5K display is an option for a perfect match as well.

The problem with 4K next to 5K is you can either:

1) Scale the 4K to the same resolution (QHD), but it may or may not scale cleanly (some application and fonts are better than others). Many have found that 4K doesn't scale the QHD very well.

https://pcmonitors.info/articles/the-4k-uhd-3840-x-2160-experience/

2) Run in 4K without scaling and gets lots of screen real-estate with a clean image, but there will be difference is size between objects on the two screens.

3) Scale the 5K iMac and 4K displays to something like 2K as mentioned above. Which may actually be a good compromise. I look forward to seeing the promised photos :) Though this will reduce your screen real-estate from the QHD level.

With a native QHD display you will be the same size as the 5K display set to best and you won't deal with any unclean scaling artifacts.

You can see why some people are very excited about the prospect of a TB3 Display to perfectly match the iMac 5K display.
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No worries Chris, I'm sure there are a lot of people in the same boat as you. It's pretty sad there's not really a good solution for a triple display 5k/4k iMac config. Will a Mac Pro power (3) 27" 4K monitors without any issues? I may have to look into the Mac Pro if this is my only option.
Yes it will. https://support.apple.com/en-us/HT202801
 
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...If you are currently using your 5K display scaled to QHD (Best setting in display preferences) then a QHD monitor like the U2715H or the discontinued thunderbolt display will have everything scaled to match perfectly. Though it clearly won't have the sharpness and detail of the 5K...

Thank you so much for this response! Honestly it sounds like the better choice is to get a reasonable QHD display right now, then get the new TB display if/when I want an upgrade.

When you said "Best setting in display preferences" did you actually mean the "Default for display" setting?

Chris
 
Thank you so much for this response! Honestly it sounds like the better choice is to get a reasonable QHD display right now, then get the new TB display if/when I want an upgrade.

When you said "Best setting in display preferences" did you actually mean the "Default for display" setting?

Chris
Yes they changed the display settings dialog from from "Best for display" to "Default for display." My bad.
 
Ok. I've narrowed my choices down to the...

DELL U2715H
or
DELL S2716DG

The U2715H is an IPS panel.
The S2716DG is a TN.

The U2715 is marketed as a general purpose monitor and has a little slower refresh than the S2716, which is marketed as a "gaming" monitor.

I'm leaning toward the U2715 because it is an IPS, which I think is a newer technology.

Both are about the same price (U2715 is about $450, S2716 is current on Amazon for $550).

Thoughts?

Chris
 
Ok. I've narrowed my choices down to the...

DELL U2715H
or
DELL S2716DG

The U2715H is an IPS panel.
The S2716DG is a TN.

The U2715 is marketed as a general purpose monitor and has a little slower refresh than the S2716, which is marketed as a "gaming" monitor.

I'm leaning toward the U2715 because it is an IPS, which I think is a newer technology.

Both are about the same price (U2715 is about $450, S2716 is current on Amazon for $550).

Thoughts?

Chris

IPS is usually best at colour accuracy and viewing angles, so good for graphical work.

TN has a faster response time, so better for gaming.

I would go with the IPS.
 
IPS is usually best at colour accuracy and viewing angles, so good for graphical work.

TN has a faster response time, so better for gaming.

I would go with the IPS.
Yes, and IPS will be a closer match to the iMac display. IPS is much better for everything except refresh rate (which is only critical for gaming).
 
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