3rd Monitor detected but I can't extend my desktop to it

[Kroeckinator]

I currently have a Radeon R9 270x with 2 DVI ports, 1 HMDI port, and 1 Display port. I am trying to get the third monitor to work, and in AMD Catalyst Control Center, it appears under "Detect Displays", but appears as "disabled". I have one monitor hooked up via DVI to DVI, another hooked up via DVI to HDMI, and the last one is DVI to HDMI with an ACTIVE HMDI to DP adapter connected to it. I can get any 2 monitors working at a time, but I can't enable all three of them together. Any help would be appreciated, thank you!

 

[maxwellmelon]

http://support.amd.com/en-us/search/faq/170
AMD rules for multi-monitors

are all three displays identical?

 

[Kroeckinator]

http://support.amd.com/en-us/search/faq/170
AMD rules for multi-monitors

are all three displays identical?

They are all the same resolution, the one in the middle is a few inches bigger though.

 

[maxwellmelon]

http://support.amd.com/en-us/search/faq/170
AMD rules for multi-monitors

are all three displays identical?

They are all the same resolution, the one in the middle is a few inches bigger though.

that means there not identical displays as the one in the middle is a different model. hence your issue.

Do these three monitors have display ports? if so a MST hub may be an option

interesting that amd shows this as a limit on the 270/280 models but the 260 and 290 are not shown to have this restriction