Problems with 2nd monitor on iMac 27

[Maccie66]

Hi, I am having problems with my iMac 27 running a 2nd monitor. Just bought a Iiyama ProLite XB2779QS-S1 27" which has a max resolution 2560 x 1440. I connected it using the mini display port (thunderbolt) to HDMI adapter which I already had but the monitor will only display in 1080p (1920 x 1080).

I googled the problem to find an answer which said I need to connect the monitor using the display port so I purchased the iWantit IMDHDD13 Mini DisplayPort Adapter which is a 3 in 1 adapter and used the display port cable that came with the monitor. The problem I now have is the monitor is detected but is just black. If I make any changes it flashes momentarily and then goes black again.

If anyone has any ideas they would be greatly appreciated.

 

[tomtendo]

Hi, I am having problems with my iMac 27 running a 2nd monitor. Just bought a Iiyama ProLite XB2779QS-S1 27" which has a max resolution 2560 x 1440. I connected it using the mini display port (thunderbolt) to HDMI adapter which I already had but the monitor will only display in 1080p (1920 x 1080).

I googled the problem to find an answer which said I need to connect the monitor using the display port so I purchased the iWantit IMDHDD13 Mini DisplayPort Adapter which is a 3 in 1 adapter and used the display port cable that came with the monitor. The problem I now have is the monitor is detected but is just black. If I make any changes it flashes momentarily and then goes black again.

If anyone has any ideas they would be greatly appreciated.

HDMI only goes to 1080p. You need DVI to Thunderbolt. I'm not sure about your second part.

 

[Maccie66]

Thanks for that, the monitor has a display port socket and that does support the 2560 x 1440 but I am using an adapter to connect the mini display port (thunderbolt) to the display port cable from the monitor.

I think that's where it is going wrong, instead of an adapter I think I need a cable with mini display to display port and not use the adapter. The iMac is recognizing the monitor but it isn't displaying.

 

[p3ntyne]

HDMI only goes to 1080p. You need DVI to Thunderbolt. I'm not sure about your second part.

Not exactly true.

Every version of HDMI since 1.3 (2006) has been able to run 1440p at 75Hz (at least) - the latest version can even run 4096x2160p at 60Hz. Also, for 1440p over DVI requires an expensive dual link adapter/cable.

To the OP, your setup should be fine. Are you sure that none of the components are faulty. I'm imagining the original HDMI cable you used was <1.2.

 

[Maccie66]

Not exactly true.

Every version of HDMI since 1.3 (2006) has been able to run 1440p at 75Hz (at least) - the latest version can even run 4096x2160p at 60Hz. Also, for 1440p over DVI requires an expensive dual link adapter/cable.

To the OP, your setup should be fine. Are you sure that none of the components are faulty. I'm imagining the original HDMI cable you used was <1.2.

The problem wasn't with the HDMI cable (which was 1.3) but with the mini display port to HDMI adapter. It was the same with 3-in-1 adapter that I tried when using the display port cable, I just don't think they're up to the job.. I ordered a 1 piece mini display port to display port cable and that solved the problem.

Thanks for all your help though.

 

[p3ntyne]

The problem wasn't with the HDMI cable (which was 1.3) but with the mini display port to HDMI adapter. It was the same with 3-in-1 adapter that I tried when using the display port cable, I just don't think they're up to the job.. I ordered a 1 piece mini display port to display port cable and that solved the problem.

Thanks for all your help though.

Great! I was thinking something was faulty.

Glad you got it working.