I have an AMD R9 280X in my mac pro running OS10.9.5 ( mavericks )
Strangely only two displays work simultaneously. All ports work fine but only a combination of two.
( DVI plus HDMI , two minidisplayports , DVI plus one minidisplayport , One minidisplay plus HDMI. )
What am I overlooking? In the description it says the and R9 280x should work with all displays simultaneously.
hope there is someone who can help me solve this.