Dual Monitor - Mac Cinema HD Display

[trickyur]

I'm working on a 20-inch iMac (early 2008) operating on OS X 10.9.5.

I'd like to use my Cinema HD Display as a dual monitor but am running into problems. My iMac doesn't have the thunderbolt input that my Mini DisplayPort to Dual-Link DVI Adapter needs. This would help the pixelated resolution I'm experiencing (the monitor is stuck at a resolution of 1280 x 800, and won't go higher despite the display’s native 2560 x 1600 resolution).

Is there a thunderbolt to mini display port adapter/converter that I'm unaware of? Or am I just screwed?

 

[chscag]

Maybe I'm missing something here, but according to specs your 2008 20" iMac has a Mini DVI output port. Thunderbolt is backwards compatible with the MiniDisplayPort. You state your iMac doesn't have a Thunderbolt input which I assume you mean "Thunderbolt Port".

I gather you're using a Dual Link DVI adapter to MiniDisplayPort to your Cinema Display and not able to get the full native resolution the Cinema Display is capable of? I don't know off hand if an adapter is available that you would need, or if your 2008 iMac is even capable of driving the Cinema Display at 2560 x 1600. Our Moderator "bobtomay" is someone who possibly can answer your question, so hang on until he has a chance to see your post.

 

[trickyur]

Yes, you are right in assuming I meant Thunderbold Port when referring to a "Thunderbolt input" and I am using a Dual Link DVI adapter to MiniDisplayPort. Even if I can't get the full resolution the Cinema Display is meant to have, anything would be better than 1280x800 resolution

My apologies and I look forward to bobtomay's response. Let me know if you need any further information from my end.

 

[bobtomay]

I'm missing something here also with the questions pertaining to displayport and thunderbolt ports.

There is only one display Apple has ever made with a native resolution of 2560 x 1600 and that is the 30" aluminum monitor and it has only a DVI port. You would have no need for any displayport or thunderbolt connectors for this monitor.

If what you have is the current model 27" "Thunderbolt Display" (native resolution of 2560 x 1440) rather than the older "Cinema Display", that's a diffferent story.

Which display do you have?

 

[trickyur]

My second monitor that I'm having trouble with getting better resolution is an Apple Cinema HD display - 30-inch DVI‬.

Sorry for the confusion but I really appreciate your help.

 

[bobtomay]

If you have purchased a mini displayport to dual link DVI cable, you may as well return it. There is no use for it on your computer and monitor combination.

Dual link DVI is not supported from a mini-DVI port. You are not going to get to dual link DVI output from a mini-DVI port no matter what combination of adapters you plug into it. The Cinema Display requires a dual link DVI to display at it's native resolution.

Your only option for connecting those 2 devices together is with a mini-DVI to DVI adapter and a DVI-D cable.

However, You should be able to get to a 1920 x 1200 output. This is the max resolution for single-link DVI and mini-DVI and is supported by the monitor.

If you do not have that resolution available for selection, my first question would be how long is the DVI cable you're using? Many DVI cables over about 15' are not be able to provide that resolution. If your current DVI cable is under 15' in length, your next option is going to be to try a different miniDVI to DVI adapter and different DVI cable.

If you go looking for another mini-DVI to DVI adapter, I'm pretty sure monoprice.com still has them. Haven't seen anyone with a mini-DVI to DVI cable in a couple years.