I am trying to connect iMac to 2 other monitors as well as my TV. That is a total of 4 displays. HERE IS MY PLAN!!!-(I'm not rich)
I have a 21.5 inch iMac that has one thunderbolt port but can also be used as a mini-dvi port. I want to connect that to a Cirago HDX3DP01 HydraDisplay X3 DP to 3 DP Multimonitor Adapter This in theory will allow me to connect to 2 monitors with an open slot for my TV. I do question the resolution output. The HydraDisplay supports up to 3840 x 1024 (3x 1280x1024). I'm not sure what that means. Which resolution is it? I know that the 21.5-inch iMac has a native resolution of 1920 by 1080 pixels, while the 27-inch iMacs are 2560 by 1440 pixels. This means at top resolution of the HydraDisplay is cannot support the native resolution of the IMac 21.5 nor the 27-inch. Will this matter when mirroring or sharing the screens as one? (disregarding the TV)
So, I have several questions:
1. Will this work?
2. Is resolution a big deal when sharing screens?
3. Has anyone ever tried this or have a better way of doing it besides expensive thunderbolt?

2 Answers 2


From the link I can only find the interface used is DisplayPort (not Mini Display Port or DVI) which to my knowledge are different standards which means item 1) would not work

For item 2) what is the purpose of having multiple displays? Are you repurposing extra displays or actually have an alternate need?

For item 3) I use a USB display monitor which allows me to connect multiple additional screens trough different USB ports in addition to my standard display out.


I have three screens....

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I'm using a kensington universal adapter to add the extra one - I've ordered another (expecting delivery today actually) so I should be able to run four... will let you know how it goes...

EDIT - adding another kensington adapter did work...

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EDIT2 - as a follow up I should mention that this is running Lion (worked with snow leopard) and to run the Kensington adapter on OSX you have to download drivers from the manufacturers site. Regarding CPU usage - there is an overhead - but it does depent on what you are doing with the screen. If you are playing a video it's really interesting to see what happens to CPU load when you move the video window from one screen to another...

  • What is the performance like, does it work ok with Mountain Lion? A lot of people report extra CPU usage, is that the case with your set up?
    – user33907
    Commented Nov 1, 2012 at 14:07
  • I've added content to my answer to address this.
    – Joe
    Commented Nov 1, 2012 at 21:44

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