Existing users, 
From the read me:
"Known Issues
Due to differences in the way processor architectures calculate time, multiplayer can only be supported between like processor manufacturers. Multiplayer is supported Intel to Intel and PowerPC to PowerPC only."
:-(
Command & Conquer Generals Zero Hour
Multiplayer real-time strategy game.
Version: 1.0.4
No Intel Mac v. PowerPC Mac netplay
Feedback Type: Commentary
Contributed by: Lakespace Thursday, December 07 2006 @ 02:35 PM PST
Product Platform: MacOSX
Used Product For: Over One Year
Comments
No Intel Mac v. PowerPC Mac netplay - sk8rdal
Intel Mac vs PowerPC Mac will work as long as you don't install this patch. Of course the game play will be extremely slow but its playable. "Check Info" of your C&C Generals app to see that it says version 1.0Saturday, July 04 2009 @ 06:37 AM PDT
No Intel Mac v. PowerPC Mac netplay - tguba
This was helpful...However, when I installed and updated C&C generals and/or zero hour on three Intel iMacs in our media lab and tried to connect via NETWORK, I still had an incredible amount of issues in every configuration. I could get the three to see each other only sporadically and often all chats were double sent...
I updated to the 1.02(zero hour) and 1.04 (Generals). I have tried direct connect as well.....
No dice...
any hints on making this work or anyone with a success story on a LAN?
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Saturday, April 26 2008 @ 12:53 PM PDT