R9 290 Triple Monitor not working

[ntDonut]

Hey, I've finally installed Mojave with moderate success on my computer.

CPU i7 9700k oc@5GHz
16GB 3000MHz DDR4
Asus R9 290 4096MB GDDR5

Just finished the installation and I got the GPU working OOB, that was great! However, I have 3 monitor setup and only 2 are showing up on MacOS and giving image.

1st monitor is on DP using a converter to HDMI -> Working
2nd monitor is on DVI using a converter to HDMI -> NOT Working
3rd monitor straight into the HDMI port -> Working

If I unplug any monitor, for exemple the DP cable, without me doing anything the 2nd monitor starts working and if I replug the DP monitor, I got no image on the DP montior.

Using the default framebuffer that MacOS assigned, no kexts so far.
Clover auto inserted the following values;

VRAM: 4096MB
PORTS: 04
FAKE ID: 0x67b01002
INJECT ATI = YES
FRAMEBUFFER: HAWAII (with double "I")
GRAPHICS ENABLER = YES

Update #1: Installed WhateverGreen and Lilu kexts, card shows up as "AMD Radeon R9 290/390 4096 MB" instead of "AMD Radeon HD 8xxx"

 

[macmini]

its probably because AMD cards of this age only have 2 TMDS transmitters which means you can only have a maximum of 2 DVI or HDMI displays plugged in at any given time

if you wish to plug in more, you need to use an ACTIVE, display port to HDMI or DVI adapter (its important that its an Active adapter and not a passive one) hopefully this helps

 

[ntDonut]

its probably because AMD cards of this age only have 2 TMDS transmitters which means you can only have a maximum of 2 DVI or HDMI displays plugged in at any given time

if you wish to plug in more, you need to use an ACTIVE, display port to HDMI or DVI adapter (its important that its an Active adapter and not a passive one) hopefully this helps

Hey, thanks!

Soo, if I try to use a DP to HDMI (active) instead of a passive like currently, a direct HDMI to GPU and a passive DVI to HDMI, I should get all 3 monitors connected if I understud it correctly, right?

 

[macmini]

Yes indeed that should provide you with 3 working monitors

just make sure the DP to HDMI adapter your are using is an active one

 

[JoQ]

Oh, I have the exact same issue, and was about the create a thread about this. Happy I found this one.
I have the same settings in Clover, and it seems to be working, except my third display. I have two displays connected to each HDMI port, and one to the DVI.
I don't need one of the HDMI-displays in Mac OS, but I don't want to keep disconnecting it. So is it possible to make Mac OS only use one DVI and one HDMI? As it is right now with all 3 connected, only the two HDMI displays are working. I have to disconnect one to be able to use DVI.

Another thing I noticed is that when booting I can see green lines over the black screen with the apple-logo. Why is this? It doesn't show when booted though!

EDIT: If it is a restriction on the card itself with only using 2 at a time, how come it does work in Windows?