Does the iMac G5 support dual monitors?

This is from the Apple site (for the G5 iMac)

"Treat your friends to a slideshow of your latest vacation photos right on TV. All iMacs offer a mini-VGA port so you can use the Composite/S-Video adapter to mirror your iMac display on television. You can also mirror your creative output to an external projector via the Apple VGA Display Adapter (adapters sold separately)."

This firmware hack (ScreenSpanningDoctor) will allow you to use the second monitor as an extended desktop.
http://macparts.de/ibook/
Visit the forum there to learn all about it

It does not support DVI

eyeMac G5 2.1 Mac OS X (10.4.4)

The iMac G5 will allow you to connect another monitor which will mirror (contain the same thing as) the iMac's display. The iMac G5 has a mini-VGA connector.

The unsupported firmware hack mentioned by the other poster can void your warranty.

It might void the warranty—I'm not going to address that since I don't know the answer; an Apple person might be able to answer it.
I have installed "ScreenSpanningdoctor" however, on my G5 iMac with no issues whatsoever. Works like a charm!
I'm using it to extend the desktop to a 19" GS790 CRT by ViewSonic. There's been no problems and I've been using it for a few weeks now.
Previously I used the screen spanning technology provided by Apple with a Quicksilver tower G4 800 and it worked fine. That had less power than the video card in this G5 iMac so I figured the card would have no problem with the extra power used and it doesn't. I'm not going to recommend this beyond what I can say about it. It's up to each of you to make your own decision about it, but I'd at least recommend checking out the web site for the software.
Here's the site to get the download, which is free by the way. Read the "read me" first to see if your computer has been checked out for the software.
http://www.rutemoeller.com/mp/ibook/ScreenSpanningDoctor.dmg

iMac G5 Mac OS X (10.4.4) 1 gig Ram

Only the new Intel iMacs have dual-monitor capability with DVI and VGA. G5 iMacs have just mirroring VGA capabilities as stated in the posts before.

VGA only
I use a Viewsonic 17"
and screen spanning doctor
works like a charm
obviously the graphics card is capable of
this without any side effects
I guess they just wanted to use spanning
as an marketing upgrade for the power macs
If you have a warranty issue you can just uninstall it

If you have a warranty issue you can just uninstall it

They can still tell you've hacked the firmware, which is the problem, not screen spanning doctor itself.

That's where you are wrong.
Screen spanning doctor is not a program or hack
it is a simple applescript that sets a parameter in
the firmware from 0 to 1.
The ability to span is built into the graphics card.
It was probably turned off as a marketing tool to
move power users from the iMac to the powermac G5.
There is absolutely no problems using this feature.
There really is no excuse for Apple to have left this feature dormant.

There is no way to undo this if the iMac won't boot. Therefore when Apple starts troubleshooting, they will discover the hack.

In that respect you may be right. However, I want to use
my second monitor in spanning mode so I'm not really concerned
about the obscure consequences. The spanning ability is built in and
usable. It is not negatively effecting the computer in any way.
I also have never seen a decision by Apple to disallow a
warranty claim because of this occurrence. Although I have heard
allot of people speculate about it.

FWIW, although I have never heard of a problem with the G5 imac, there have been a few people with the G4 imacs who've come here because they fried their video with the hack. Just a few, but it is NOT foolproof.

It is not negatively effecting the computer in any way.

There has been some speculation that spanning has been disabled in iMac G5's because of excess heat issues, the idea being that the video card works harder, producing more heat than the iMac's cooling system was designed for.

I'm not sure how valid a concern this is, but it might be worth checking the internal temp of your iMac with spanning on vs. off, using something like X Resource Graph (freeware) to monitor fan speed & temperature. My guess is that the worst case would occur when the external monitor is set to a substantially higher resolution than the iMac itself supports.

I don't know if or to what extent mirroring is "easier" on the iMac, but this is also something that a comparison test using X Resource Graph should tell you.

I'm sure many folks would be interested in the results you get, so please post them here if you are willing to do the test(s).

For 3 years I ran a ViewSonic 17" monitor in spanning mode with
my Powerbook 867Mhz G4 12" with absolutely no ill effects.
That Viewsonic is now spanned to my iMac G5 20"
I always keep Temperature Monitor up and running when using
either computer. I have never noticed any difference in temperature
of the CPU or GPU with spanning enabled on either computer.
There is absolutely no reason that spanning on the iMac G5 should be
a concern. It has the capability built into the graphics card, the cooling and processor power to do it.

I have never noticed any difference in temperature
of the CPU or GPU with spanning enabled on either computer.

This is good to know. My iMac G5 isn't a particularly "cool" computer (temp-wise, anyway), so I have been reluctant to try spanning. Maybe I will now.

Thanks for the info.

There is absolutely no problems using this feature.

I decided to give SSD a try & indeed it works well with my iMac -- no heat issues I can detect.

The only oddity so far is with the Desktop picture option. (For those that haven't tried it, you can set the Desktop & Screensaver preferences for each screen individually when in spanning mode.) While I playing around with this, I decided to check out the "change picture" option for the external screen, choosing a 5 minute rotation for the same folder of desktop pix I use for my screensaver. That worked fine, except when I later disabled the change pix option, it didn't "take" -- the desktop background contines to change at 5 minute intervals, using the pix from the same folder.

This continues, even if I turn the option back on & change the interval, the folder, or both. Also, changing any options to center, tile, stretch, etc. the desktop pix briefly "take" & reinstate the chosen pix, but 5 minutes later, the pix rotates to the next folder one & these options also revert to the one initially chosen.

It is a minor annoyance, but one I'd like to eliminate. Any ideas on this are welcomed.