r9-270x Triple monitor setup not displaying (no Eyefinity)

[Toonster17]

Hello everybody,

A buddy of mine recently bought 2 Asus 27" monitors together with a Sony TV and planned to hook it all up to his r9-270x AMD Toxic Saphhire card. One of the Asus monitors and the Sony TV have a display, but the 2nd Asus does not. At the moment he has the Sony connected via DVI-HDMI Adapter, one of the Asus monitors is also connected via a DVI-HDMI Adapter, the other one via straigth HDMI.

Any tips/advice?

 

[Rookie_MIB]

That card should have the following outputs: DVI-I (which is analoge and digital outs), DVI-D (digital only), HDMI (digital), and Displayport (digital)

You have the DVI-I (w/adapter), DVI-D (w/adapter), and HDMI. Which output isn't working? Apparently the Sony is working (one of the DVIs) - but which Asus monitor isn't working - and which port is it connected to? The DVI-I, the DVI-D, or the HDMI?

 

[Toonster17]

The Asus monitor which isnt showing an actual display, but IS showing in the Windows display settings, is the one connect via HDMI-HDMI.

 

[Rookie_MIB]

A little digging brings up the problem. The R9-270x will support up to six display outputs, IF they are all DisplayPort. However, the graphics engine can ONLY display up to two 'legacy' outputs at any given time. So, you could have 1 legacy port, and 5 displayports, or 2 legacy ports, and 4 displayports. So - what does AMD consider a 'legacy' port?

VGA. Legacy.
DVI (I/A/D). Legacy.
HDMI. Legacy (this is absolutely mind blowing!)
DisplayPort. Non-Legacy.

So - the net result is that you're trying to run three 'legacy' ports off the card - which is not supported by the hardware. You can run the two DVI's, or one DVI and one HDMI - but the third display MUST be connected to DisplayPort to work. This one is nice and simple:

http://www.startech.com/AV/Displayport-Converters/DisplayPort-to-HDMI-Active-Video-and-Audio-Adapter-Converter-DP-to-HDMI-1920x1200~DP2HDS

Here's the other thing, you must use an active adapter from the displayport. You can have a passive DP to HDMI, but the problem you'll run into is that the DP will be connected to one of the two legacy driver clocks and you'll still only get two displays. With the active adapter, the card thinks it's just outputting the DisplayPort raw signal, the conversion happens after the fact - thus 'tricking' the card into using the DP clock with that output, leaving the other two monitors for the 'legacy' connections. So - you'll run one DVI (use the DVI-D), use the HDMI, then get the active converter and go HDMI from the adapter to HDMI.

So that's why it doesn't work. Once you understand what AMD considers a legacy port, the solution becomes pretty obvious.