PC Drivers & Software

[whycantitjustwork]

I have a SIIG display port 1.2 MST splitter. It works fine with an nvidida GPU i have, but not with any AMD GPUs. I have multiple AMD GPUs and none work.

What happens is that 1 monitor will work, and the other does not get any signal. I can unplug the working one, and the other one will start working. With the same setup, I can use a 1070 and it works fine. 

The AMD GPUs: https://www.xfxforce.com/gpus/amd-radeon-tm-rx-570-rs-8gb-black-edition-only-at-best-buy

I have tried reinstalling drivers, uninstalling drivers, removing device, reinstalling, etc. Tried current driver and previous.

When I go into Windows 10 Display Settings, I can see the monitor that's not on. It's a tiny box with no resolution set, and set to "Disconnect this display". When I try to extend it, it says "display settings could not be saved..." and it never turns on.

I've gone through the "AMD Radeon Software" program looking for potential settings like Eyefinity, but I don't see anything. 

Any ideas why this isn't working?

[whycantitjustwork]

Screenshot of windows display settings. There's 6 monitors (GPU supports 6 monitors). Only 1 monitor per splitter works. Also if I just do 2 monitors total it's the same result. For some reason, AMD drivers don't want to allow MST. 

[elstaci]

How exactly do you have all 6 monitors connected to the RX570 with what Resolutions and Frequencies?

Make & Model of all 6 Monitors.

I noticed that the monitor showing in your second post has 2 HDMI and 1 DP Input.

You say that you have 3 MST with two monitors connected to each MST?

Have you tried connecting 3 or more monitors to one DP Output on the RX570 using MST to connect all 3 -6 Monitors?

Also do you have both Nvidia and AMD GPU cards installed on the same computer?

According to SIIG DP 1.2 to 2 Monitor splitter this are the maximum Resolutions and frequencies for that specific MST: https://www.siig.com/displayport-1-2-mst-to-2-port-displayport-splitter.html

Resolution:

• Single output: Up to 4Kx2K @60Hz
• Dual output: Up to 4Kx2K @30Hz or 1920x1080 @60Hz

Could be you are maxing out the Resolutions with 3 monitors connected.  But you also mentioned everything works fine with 6 Monitors connected using the Nvidia GPU Card.

[whycantitjustwork]

1) They're all connected with display port. Alienware AW2720HF monitors which are 1080p 244hz, but windows automatically set them to 60hz.

2) I'm using 3 display port MST hubs (1x2 each), running 6 display port cables to 3 splitters, and the splitters into the GPU. 

3) I only have 1 GPU installed at a time

I have an additional HP Omen gaming desktop that happens to have an RX 580 in it (not sure the brand). It also cannot use the MST hubs.

I also tried a Startech MST hub which doesn't make a difference.

The 1070 GPU will work with identical setup. I just go into display settings and extend the monitor and it works. No AMD GPUs have worked for me. 

There are only a few things I can think that would cause this:

1) BIOS settings that conflict with AMD cards

2) Bug in drivers/firmware, but I tried 2 versions of drivers so seems unlikely

3) Settings that must be enabled in AMD Software

I would really like to know if anyone actually has a RX 570/80 that is also running an MST hub. I might be able to try a Radeon VII to see if that works. 

[elstaci]

I see that the DELL Monitors doesn't have any DP outputs on them so you can't Daisy-Chain them.

This company sells MST hubs with one DP input and up to 4  DP/HDMI Outputs: https://www.tripplite.com/products/a-v-digital-signage~2?2127=MST%20Hub

From the same company from above link showing how to connect several Monitors to one MST Hub: https://blog.tripplite.com/how-to-connect-a-single-displayport-signal-to-multiple-monitors

Maybe you can use a 4 Monitor MST HUB and then directly connect the other 2 Monitors to the GPU card if it has 3 or more Video Outputs.

EDIT: Decided to make sure your RX570 support 6 Monitors and it does according to CNET for the XFX RX570 GPU Card:

[whycantitjustwork]

Appreciate your input! You have given more input than any manufacturer support has!

The MST doesn't work even with two monitors. Thus I don't think a different hub will work. I tried startech and siig hubs. 

I have tested the 570 rx black 8gb and also a rx 580 from a HP desktop, but neither work. I have a 5700 xt and a radeon vii I'll try in a day or so. 

I am talking to support with amd, xfx, siig, startech, dell, and so far everyone just shrugs and gives the run around. 

By the way, almost all xfx gpus support 6 monitors. That's assuming mst works though .... 

I updated bios today but didn't change anything 

[whycantitjustwork]

Today I tried a Sapphire 5700 XT and it did MST fine. I didn't even have to extend the monitor, it just came on. Can't believe the 570 and 580 GPUs won't just work.

[elstaci]

So do I.

I do know that you can hook up 6 monitors, at least , by Daisy-Chain method. The Only thing I can figure is that somehow the Bandwidth connected the way you had it was greater than the GPU card can provide or something in those GPU Cards just wasn't compatible using more than 1 MST hub.

But happy to hear you finally was able to connect all 6 Monitors using 3 MST Hubs.

Please mark your last reply as "Correct" or "Solution" so other will know what you needed to do to fix your problem.

Take care.

[whycantitjustwork]

I'm not able to connect all 6 with MST hubs. Using the 5700 XT isn't a solution, but a test to see if it's an AMD issue. I want to use the RX 570, because it supports 6 monitors. The 5700 doesn't. The 5700 was able to support 4k monitors. MST hubs can easily support the bandwidth of 1080p monitors at 60 hz.

I installed Ubuntu 20 desktop and all 6 monitors worked fine on the RX 570 GPU (the GPU i have been trying to get working). That's using open source generic drivers that are default in Ubuntu. Sadly I need Windows to run some programs, otherwise I would just use Ubuntu.

I also disabled Windows 10 automatic driver installation, then removed the AMD drivers, and the MST hubs worked in low resolution. They work in the BIOS. As soon as AMD driver is installed, they stop working. I tried historical AMD drivers from March, September, November, and the latest one of December. None worked. 

I'm confident now that the AMD 500 series drivers all have some issue with MST hubs. I sent my findings to AMD in a support ticket, but it's as fast as molasses. 

[Odjinn]

Have you heard anyting back from AMD. Because i have the same problem, with a different setup.

[joevt]

I have the same problem with Radeon RX 580. It has two DisplayPort 1.4 ports. Nothing connected to the two HDMI 2.0 ports.

I have two 3 port DisplayPort 1.4 MST Hubs. I understand the RX 580 doesn't support DSC so it cannot do three 4K60 displays to a single MST Hub. However it should be able to do 3 displays set to 2560x1440 60Hz. But it will not. The most number of displays per MST Hub that I can connect is two. I can only connect 3 displays total. This is ridiculous. I even tried using CRU to remove all the 4K timings from the EDIDs in case Windows or AMD drivers were being dumb about reserving bandwidth for resolutions I don't want to use...

Does AMD even test this stuff?

I can  boot into Ubuntu, connect 3 displays per MST Hub (6 total), and have all the displays quickly arranged and set to 2560x1440 60Hz. Lucky the driver is open source in Linux so AMD can't ruin it. Do the Linux people just care more? Is AMD hampered by Windows requirements?

The nice thing about Ubuntu's Screen Display UI is that you can change the settings of all the displays before applying them to the GPU(s). It's so much faster (don't need to wait for each display to readjust to the new settings and don't need to click a "Keep Settings" button for every display).

For Windows, AMD needs to make their own Display Settings UI (doesn't Nvidia do that?). It's really silly that I have to use four or five different UIs (display arrangement, resolution, bpc, timing, some of these buried behind another UI). There's too many windows and too much clicking and too much wasted space and time in the current AMD Radeon Pro Software UI.

In Windows, if you select 1440p for a 4K display you might be getting a 1440p framebuffer that is scaled up by the GPU to output at 4K to the display. The Advanced settings tab in Windows Display preferences will show when the framebuffer size does not match the output resolution. The output resolution/timing can be seen in Radeon Software as well. In macOS, using the SwitchResX app, the Current Resolutions tab will indicate which modes are scaled and which modes are actual timings. Apple's UI is terrible - it doesn't show output resolution or pixel format / depth and you have no control over pixel format / depth (except the HDR setting requires at least 10bpc).

[AliSawa]

I'm fighting with MST splitter right now. (delock 87794), Radeon 6700xt

first monitor Samsung LC32HG70 to first DP port in the card (always works fine)

in second DP port splitter connected. when i connect 4x NEC V321 to splliter, and ElitePos 10TW to third DP port (through "SUNIX UPD2018"). Everything works fine! 6 displays work.

BUT

when i want connect even one (I have 4 of them)  ElitePos 10TW through MST splliter then windows see monitor, even extend desktop on that monitor but monitor stay black don't see any input. (when I connect monitor directly without MST splitter works fine)

when I connect 3x V321 and ElitePos to MST Splitter, then all V321 works fine but ElitePos black monitor, but desktop extended like it should working.

[electrico]

Exactly the same thing is happening to me now with the new 7800XT, I have gone from a 5500XT 8G that was working perfectly with my 6 monitors.
Now I can't have more than 4 on, this is a serious problem (and very frustrating).

Any solution?

[maxi1134]

I have this issue as well with a 7900XTX and 6 monitors.

Surely i did not pay 1.5KCad for a GPU that is a downgrade over the last generation, right?

Can an AMD employee answer us?

[whycantitjustwork]

What brand is the 7900? Only XFX supports 6 monitors as far as I know. If only 3 monitors work, that's usually the problem. Almost all GPUs support 3 monitors maximum.