Does the Iiyama 5k monitor work with the iMac Pro?

Now that the 10.13.4 is finally officially out with eGPU support, I can confirm:

1. The monitor will work in its full 5K@60Hz glory with a DisplayPort 1.4 compatible eGPU (I have the Sonnet + RX580 combo AKA https://developer.apple.com/development-kit/external-graphics/)
2. If you don't have DP1.4, the best you will get from a TB-DP1.2 connection is 5K@38Hz.

Re: eX&TriC's question — the monitor will definitely run at 2560×1440, but the resolution is scaled with some antialiasing and the text is not crisp.

Okay, this is not exactly the setup I have, but close.

I run a 2017 MBP 15", maxed-out. I bought both the Iiyama XB2779QQS-S1 and the Moshi 5K cable to try and get them running together. Unfortunately, I'm only getting 4K resolution (3840×2160) at best!

If the monitor is set to Dot by dot mode, it even looks crisp and nice, but only in the middle of the screen:

Using SwitchResX I'm able to get some weird resolutions like 1280×1440 (HiDPI, so actually 2560×2880) to work:

But that's about it — I'm not getting full 5K, it's 4K at best.

The Iiyama XB2779QQS-S1 has two DP 1.4 (not 1.3), and they claim they do not support MST (can't check yet).

I'm currently communicating with both Iiyama and Moshi support, but nothing helpful so far. I'm starting to seriously doubt whether Moshi cable can run this display — or whether my MBP can, as it's DP1.2 and thus limited to 4K on a single stream. I was expecting the Moshi cable to run two streams and combine them into DP 1.4 signal...

Honestly I'm quite disappointed. The monitor itself is good, even if can only use just a half of it. I would love to be able to use the whole screen.

Below 1.4 there is no 5K at all beleiving what Iiyama says.

Actually, you can get 5K from Moshi cable, just at 38Hz max — and you will need a custom resolution w/SwitchResX or the like to do it. I mentioned it above, but let's give more details.

You might also want to set "Scaled resolutions base: 5120 x 2880" on the "Display Information" tab, and also create a scaled resolution of 2560x1440.

So, I was finally able to get it work, mostly.

I actually went as far as to buy a Sonnet eGFX 550 box and RX580 (same as https://developer.apple.com/development-kit/external-graphics/) to test it all. First I tested RX580 in a Win10 PC and yes indeed, I was finally seeing 5K@60Hz on my monitor!

Then I moved on to test the eGFX box, but unfortunately the results were still the same as previously with the Moshi cable. Even though the GPU is definitely capable of 5K@60Hz, macOS still does not know about this.

I enrolled in the beta program to try out the 10.13.4 public beta, but it doesn't show up as an available update. 😟 I have found that other people are having similar issues, and the solution proposed is to reinstall High Sierra from Recovery mode — well, I'm not up to doing this right now.

Then I decided to try something else and actually fit into the DP1.2 bandwidth.

I disabled SIP, then created a number of custom resolutions in SwitchResX which went like 5120×2880@30Hz, …31Hz, …32Hz and so on. I rebooted to try them out… and some actually worked! Most were listed as incompatible, but everything at 38Hz and below does work.

I disconnected the eGFX and connected directly with the Moshi 5K cable. IT WORKED AGAIN!

Currently I'm running at native 5120×2880@38Hz, in glorious 2x retina, on macOS 10.13.3 via a single cable.

Image quality is very good and I'm pretty happy.

I would be happier if I had 60Hz though, but I guess it's now up to Apple and Iiyama to figure this all out. I hope I will be able to use the eGFX box for this later when 10.13.4 is out.

I have also noticed that the monitor is wrongly detected as PL2779QQ by default (as a non-retina monitor they released several years ago). Maybe it has something to do with it reporting wrong capabilities.

Anyway, I hope someone at Apple will notice this thread. I've asked them on Twitter, still waiting.

Hi, i'm also interested in this monitor and I found a DisplayPort cable to usb-c that supports 5k resolution and it's made for new macs.

Check this out:

https://www.moshi.com/usb-c-to-displayport-cable-5K

With this cable it will work.

If you will try this combo reply here.

Good review,

I did some research and I think another solution is to connect two dp calbles and plug in the macbook.

This is what i saw on dell 5k and hp 5k monitors.

Maybe if you can update this topic if you have something new.

I will try this with dual cable in a couple of days, when I get the StarTech dock.

Iiyama support, though, directly told me that MST (dual DP) is not supported on this monitor, but I guess we'll just have to see.

Okay, I have tried it with the StarTech dock. I can now confirm that MST (5K over dual DP connection) is NOT supported with this monitor. Best I could get was a side-by-side picture from two inputs. That's what the supplier told me would happen.

I could probably try it with just a TB3-2DP dongle, but it's rather expensive just to try something that most likely wouldn't work...

A couple of words on the StarTech Triple 4K USB-C Laptop Docking Station product id DK30CH2DPPD — it can be a good solution to some, but definitely not for me, since its DP ports are running through DisplayLink. There's a long list of associated problems (no clamshell mode, high CPU load, bad Retina handling etc.) There is something good about it though: it does charge the laptop, and it gives you a USB hub, and probably Ethernet (didn't check whether Ethernet worked without DisplayLink drivers).

tl;dr:

Two expensive options are left: trying a eGPU, or actually buying an LG Ultrafine 5K display. Haven't decided yet.

Okay, so here's the latest update. =)

Moshi support came back to me with the following statement:

We now received a reply from our product team and they confirm that the MacBook Pro 15" only supports up to Displayport 1.2 (i.e 4K@60Hz).

We have made them aware of this confusion and we are working on updating our website to make it more clear regarding MacBook Pro compatibility. While you will be able to connect your MacBook Pro to a DisplayPort display, you will unfortunately not be able to output 5K resolution, regardless of the cable you are using.

It's not like I haven't figured it all out by now, but thanks for the confirmation anyway.

Moshi 5K cable is false advertising. Intel only introduced DP 1.4 over TB3 just a month ago with their Titan Ridge chipset. There are simply no devices out there to back up their claims. Maybe you can connect an UltraFine 5K display to a PC with this, I dunno — don't care — as their advertising directly states you could get 5K with this from a Mac. You can't. (Also it doesn't work with Macbook 12" at all, just for the record — as expected, it's not TB3, just USB-C.)

Don't buy the Moshi 5K cable, it's not worth it.

Now, the LG UltraFine 5K monitor seems to be impossible to procure in Europe (unless importing from the US and/or very heavily overpriced.) So I am left with the eGFX route, since I actually want to get this to work. =)

I have contacted Sonnet to find out whether I will get true 5K from their breakaway box and e.g. a Radeon 580 card when running off my MBP. They said they are looking into it together with AMD. Will post when I get a definitive reply.

I'm documenting this extensively here in hopes that people will stumble upon this thread when doing their research and will not have to repeat my mistakes.

Hey, nice try, maybe you can give an update after you instal 10.13.4 cause i think there will be some changes.

AlzaShop it's the online shop where i bought the ultrafine.

If you have something new give us an update.

Cause i need to buy a second monitor and i can't afford another ultrafine.

Not sure if this is helpful: just tried this monitor on my Imac 2017 27. Also used the described Moshi cable.

I was not able to bring this monitor to a 5K resolution, first cable no signal at all, second cabe only 4K. Fyi: Iiyama requires a DP 1.4 cable (which the Moshi one is).

Below 1.4 there is no 5K at all beleiving what Iiyama says.

Hi,

I am interested in buying this monitor and running it at 2560×1440 because it has a number of advantages and my macbook 12 inch can not handle 5K.

Are you able to select 2560×1440 as a resolution and is the text crisp?

Thanks,

C

Looking forword for you next update. I wanna buy this monitor and i have the exact macbook like yours.

Big Thanks for your response. Yeah, i think the best solution it's the Ultrafine 5k display.

I ordered today, the Lg ultrafine 5k in Europe from a international website with excellent customer service.