27 Inch iMac - How does input work?

Brett, you toggle between using the 27" iMac's display and the external source's video by hitting control-F2 (or is it command-f2?) so quite easy to switch the source being display on the iMac. I would imagine System Preferences/Displays would indicate which combination to use. i am not an iMac owner yet but should be in a few weeks.

I hope someone who has bought more than one of the new iMacs can answer if you can connect two 27" iMacs but it seems feasible if you are only interested in the video signal as i believe there's no audio signal supported in the iMac's mini-DisplayPort connector. Apple doesn't mention hooking up two iMacs but they do give examples of hooking up a Macbook's mini-DisplayPort to the new 27" iMacs.

From the manual:
Mini DisplayPort
Output port with support for DVI, VGA, and dual-link DVI. The 27-inch model also
supports input from external DisplayPort sources. Required cables and adapters
are available separately.

I guess your selection depends upon how badly you want to use two monitors with a second iMac 27" machine acting as a monitor. According to Apple's specs, the 27" iMacs come with one of the following processors"

3.06 GHz Core 2 Duo w/3 MB L2 cache
3.33 GHz Core 2 Duo w/6 MB L2 cache
2.66 GHz i5 quad processor w/8 MB L3 cache
2.80 GHz i7 quad processor w/6 MB L3 cache and hyper-threading for 8 virtual cores

If you really want two displays, the two Core 2 Duos are going to cost more than a single quad core i5/i7. I'd go with one quad core now and see how it goes. Maybe next year Apple will have a standalone 27" display to pair with the iMac for less money of course.

Sorry about the typo, the i7 processor also has 8 MB of L3 cache, not 6! Wish I knew how to edit these posts instead of replying to my own messages.

What is the correct cable to use to connect iMac 27" as a second monitor for a laptop with VGA output connector? The cables I've seen at apple.com seem to be all female VGA, but this would need to be male VGA.

Vic-

It's not a question of cables or adaptors, it's a question of incompatible signals.

There are more details here--

http://discussions.apple.com/thread.jspa?threadID=2205633&start=30&tstart=90

--but the basic problem is that you need a DisplayPort signal to drive the iMac monitor. You can convert a digital DVI output (or HDMI which is the same thing with audio and a different physical connector) to DP format with an expensive converter, but there is no way to convert an analog VGA signal to DP format. The cheaper but more complicated solution for a PC with DVI output, and the only solution for one with VGA output, is to replace your video card with a DisplayPort or Mini-DisplayPort card. Mini-DisplayPort has the same signal but a smaller physical connector.

This was not actually Apple being arbitrary: DisplayPort is more efficient and less expensive than DVI/HDMI because it dispenses with a lot of the conversion hardware needed for that format. Therefore Apple couldn't provide DVI/HDMI compatibility without increasing the iMac cost substantially.

-JAFDC