27" 5K iMac - external "2nd" display questions

[Shadow Puppets]

I'm about to order my new 27" 5K iMac...

I plan on possibly using a second 27" monitor with it, for more screen real estate when using Logic Pro X.

Couple of questions:

1) Is the 395 processor sufficient to run the second monitor without any hiccups and slowdowns/heat issues, or would you recommend the 395X (mu budget allows for either, but I've heard the 395X might get too hot?)?

2) What is the best 27" external monitor that gets as close to the quality of the iMacs 5K screen?

Thanks in advance.

 

[Anonymous Freak]

Others have reported running an external (so second) 5K display on the low-end M380 without difficulty. I wouldn't try gaming with a dual-screen-aware 3D game at full native resolution on both, but for everyday tasks, you should be fine.

The Dell UP2715K came out at basically the same time that the first 5K iMac came out, and teardowns show that it used the exact same LCD panel - so it's as close to identical quality as you can get! There are newer 5K displays that may be even higher quality, though.

 

[Shadow Puppets]

Others have reported running an external (so second) 5K display on the low-end M380 without difficulty. I wouldn't try gaming with a dual-screen-aware 3D game at full native resolution on both, but for everyday tasks, you should be fine.

The Dell UP2715K came out at basically the same time that the first 5K iMac came out, and teardowns show that it used the exact same LCD panel - so it's as close to identical quality as you can get! There are newer 5K displays that may be even higher quality, though.

I've looked at that Dell monitor, but it appears (at least according to Dell's site) that it is now discontinued. I assume they have replaced it with a newer model, but they really aren't clear about that on their site.

 

[Shadow Puppets]

Question re the Dell monitor. Apples website suggests I will need to use both Thunderbolt ports from the iMac to power the dell screen at 5k...something that I can't do as I will have a Thunderbolt audio interface connected to one of them. Question is, will I be able to get 4K out of the screen with a single Thunderbolt cable (or via another method), and if so, will the size of fonts and icons match between screens?

 

[CWallace]

Question re the Dell monitor. Apples website suggests I will need to use both Thunderbolt ports from the iMac to power the dell screen at 5k...something that I can't do as I will have a Thunderbolt audio interface connected to one of them.

Yes, all 5K monitors currently on the market (to my knowledge) other than the new LG TB3 model require dual inputs to drive them at 5K (each input drives half the display). So you would have to dedicate both of your TB2 ports to drive it. That will be one of the advantages of the next iMac's TB3 ports as a single TB3 can drive a 5K display.

Question is, will I be able to get 4K out of the screen with a single Thunderbolt cable (or via another method), and if so, will the size of fonts and icons match between screens?

Yes, a single TB2 port can drive a 4K display. However, screen elements (windows, icons and fonts) will be of a different size unless you set your iMac's display to a 4K resolution - which defeats the purpose of having a 5K display and will result in the iMac display interpolating pixels, reducing sharpness.

 

[Shadow Puppets]

So there would be no way of getting the Dell to display icons and fonts the same size as the iMac without changing the iMacs resolution?

 

[CWallace]

So there would be no way of getting the Dell to display icons and fonts the same size as the iMac without changing the iMacs resolution?

The Dell monitor will be running below it's native resolution so the fonts and icons will be larger. It will also require interpolation, as well, since the display will not be 1:1 to the pixels (as it would be at the native 5K resolution).

 

[Shadow Puppets]

Ok, so is there an alternative 27" monitor that is maybe 4K instead but that will work with the iMac 5k with a single Thunderbolt cable and be able to display icons and fonts at the same size as the iMac in its default settings?

My OCD would never cope with varying icon sizes!

 

[CWallace]

Ok, so is there an alternative 27" monitor that is maybe 4K instead but that will work with the iMac 5k with a single Thunderbolt cable and be able to display icons and fonts at the same size as the iMac in its default settings?

What you want is a 27" monitor with a native resolution of 2560x1440 (which is a common native resolution for such a size) as that will have the icons, fonts and windows the same size as the iMac 5K. For even though the the iMac 5K is a 5180x2880 display, in the default HDPI ("retina") mode it scales the icons, fonts and windows at an effective 2560x1440 resolution - they just look twice as sharp thanks to the smaller pixels (so it uses two pixels per element whereas a 2560x1440 display uses one).

So everything will be the same size, it is just the iMac display will look sharper because of HDPI.

 

[colinsky]

What you want is a 27" monitor with a native resolution of 2560x1440 (which is a common native resolution for such a size) as that will have the icons, fonts and windows the same size as the iMac 5K. For even though the the iMac 5K is a 5180x2880 display, in the default HDPI ("retina") mode it scales the icons, fonts and windows at an effective 2560x1440 resolution - they just look twice as sharp thanks to the smaller pixels (so it uses two pixels per element whereas a 2560x1440 display uses one).

So everything will be the same size, it is just the iMac display will look sharper because of HDPI.

When I got my 2015 Retina iMac in July, I used it with a pair of old monitors, but the colors were off, and the old monitors were extremely dim and fuzzy compared to the 27" 5K screen, and the icons were all different sizes. So I junked the old monitors and added two Dell U2715H 2560x1440 monitors, one on each side of the iMac, and I am ecstatic with my wide panorama.