R9 290X, Yosemite, and Dual Displays

[Will9990]

3) Disconnect the second monitor if you have it connected, this caused me to crash at start-up.
4) When Yosemite is booted up, go up to the Apple Menu and then "About this Mac".
5) Go to "Display" and then reconnect the second monitor. (I've used DVI on the first monitor and on this step, I reconnected the second DVI port to another monitor).
6) Hey presto, this should have your dual screens.

Thank you for getting an answer for this problem, just a few questions,

Do you have to unplug and plug the monitors in at every start up?

Is Sleep/wake working properly?

Also, what settings do you have for the iGFX in your bios? how much VRAM etc?

Thanks.

 

[ellidi]

As I understand it there is currently no solution for a dual monitor setup with an r9 290x unless I have an iGFX on my motherboard. Is this correct?

 

[Will9990]

As I understand it there is currently no solution for a dual monitor setup with an r9 290x unless I have an iGFX on my motherboard. Is this correct?

from what I have read, yes. You could try enabling IGPenabler. Not sure whether that'll have the same affect?

 

[ilmastro]

So frustrating... Does anybody know about a future support for dual displays? Or an alternative way, unless an internal video card

 

[aicragleon]

To get 290x with dual monitors / multi monitors (works with 3 for me) boot with one monitor, put computer to sleep, then plug in 2nd monitor (or 2nd and 3rd), then wake the computer, profit.

I have a 290x on Yosemite using Clover with an x79 board. I found this out after hours of troubleshooting. The only thing I changed in the config.plist was to use Hawaii framebuffer, and if you have a problem with dual monitors then you probably don't have to worry about this since I have the same problem as everyone else. Tonight I will experiment with a script to put the computer to sleep at bootup to see if having 3 monitors connected will work after sleep and wake, or if OS X has to boot with only one monitor. This answer will come soon since I am on my way home now. The script was from the old 7970 days when a sleep trick was the fix for that. I will post the source for this and instructions on my next post.

 

[destrekor]

I haven't got two R9 290X to test this but I'm able to use two DVI ports and a HDMI port on one card and able to get triple monitors to work.

Now that I own a 290x (MSI 290x Lightning), and, technically own two of them (the first I ordered is at MSI under RMA; can't wait to have two working cards!), I am prepared to re-do my OS X installation.

It had problems in other ways, and I kind of killed my Clover boot, so I don't know how the card will behave.

With that clarified, I am curious about one thing: does your method work permanently, or require messing with the connections every time you perform a hard boot?

I will be dual-booting between Windows and OS X, because I'll be gaming with Crossfire under Windows, and I refuse to deal with that mess of disconnecting and connecting various monitor cables every reboot into OS X.

There is also the iGPU method I have seen people mention, but I dislike the idea of not even seeing my POST/BIOS screens, or Clover/Windows Boot for that matter. Frankly, I'm worried that I wouldn't even be able to see the F8 menu for Windows prior to full boot if I have to enter safe mode or other recovery options.

 

[ellidi]

To get 290x with dual monitors / multi monitors (works with 3 for me) boot with one monitor, put computer to sleep, then plug in 2nd monitor (or 2nd and 3rd), then wake the computer, profit.

This worked! Thank you!

 

[aicragleon]

destrekor,

I do have to do it at each reboot, but I actually have a KVM switch hooked up to both monitors and have one switched off at boot, then put computer to sleep, then switch to the monitor, then wake. I think a simple cheap HDMI switch would work for this too. This may be the only way for those of us without igpus to get dual monitors at this time. I tried sleep scripts but they did not work. It seems that os x needs to boot with only one monitor first, then go to sleep. The second and third monitor can be hooked up any time after that, during sleep or after wake. Check eBay for cheap HDMI switchers if you don't want to unplug and replug the HDMI every time. I am currently using a siig CE-KV0111-S1 hdmi kvm switch for this task, pretty expensive but I have a different purely HDMI swithlcher on order from eBay that should also work. I will let you all know if it does, but I don't see any reason why it would not work.