Yosemite on Radeon R9 280x with 3 monitors?

[toxicfume]

How do I get the drives to show up with CSM disabled, then? One of the drives that disappears with DSM disabled is an SSD, I would imagine that one to work, at least, no?

 

[qbe]

i had similar problem which i narrowed down to frame buffer. I found two solutions:

1) boot with two displays, sleep and after wake up all three monitors are working

2) boot using integrated Intel gpu on first monitor, and two other monitors on amd gpu

option 2 is more elegant and very hassle free

i tried editing frame buffers, but even using the tools and information i couldn't make working frame buffer, so i quit after two days and used option two

 

[Manic Harmon1c]

i had similar problem which i narrowed down to frame buffer. I found two solutions:

1) boot with two displays, sleep and after wake up all three monitors are working

2) boot using integrated Intel gpu on first monitor, and two other monitors on amd gpu

option 2 is more elegant and very hassle free

i tried editing frame buffers, but even using the tools and information i couldn't make working frame buffer, so i quit after two days and used option two

Yeah, i don't think a single person has had luck with 3 monitors on a R9 2xx card by patching the framebuffer... Just 1 person who was able to do it by disabling csm and enabled windows 8 whql mode with Clover.

 

[toxicfume]

i had similar problem which i narrowed down to frame buffer. I found two solutions:

1) boot with two displays, sleep and after wake up all three monitors are working

2) boot using integrated Intel gpu on first monitor, and two other monitors on amd gpu

option 2 is more elegant and very hassle free

i tried editing frame buffers, but even using the tools and information i couldn't make working frame buffer, so i quit after two days and used option two

Interesting! Thanks for the reply. I did *once* get all 3 monitors working and I was shocked, now I realized it was after waking the machine up from sleep. It never got working again.

Option 2 sounds good, but wouldn't it be weird if I ran any programs that use graphics acceleration? For example if I started a graphics-heavy game, how would the system handle acceleration when both Intel and amd gpus are being used?

 

[iGFORC3]

The most ATI cards can't run the HDMI and DVI Port at the same time in OS X. So try to hook up 2 display via the miniDP ports and the other one via DVI. Would be nice 2 know if that worked out, i'm planing am similar setup with 3 Displays and a MSI R9 280X.

 

[Total_Noob]

Just a note to say that I got three monitors working on a Gigabyte 280x using two DP and a DVI.
I couldn't get them to wake when the system sleeps, but that's a well known issue it seems.

It's 9-5 work setup, so I keep the system awake all the time and just let the monitors sleep and they wake fine like this.