My buddy and I have been playing Age of Empires 3 on a LAN for a while now. We have only played 1 on 1 games. Recently we've tried playing with computer players added, and the game almost always freezes about 10 minutes into it. Here's some info about the setup:

Host computer:
Phenom II X4 940
Nvidia 8800GT
4GB ram
Running Windows 7

Other computer:
Athlon 64 3200+
Nvidia 6600GT
1GB ram
Running Windows XP Home SP2

We used to connect through a Linksys WRT54GS router. It worked fine with only us two playing, but when we add computer players, the host computer almost always freezes, even with the graphics settings turned all the way down. We have to do a hard reset.

I switched to using just a Netgear FS605 switch to connect, and we were able to play an entire 40-minute game with 4 additional computer players and the graphics settings maxed. The next day, we tried again with only 2 additional players, and it crashed within 10 minutes. I turned the graphics settings down, and we played with 3 computer players, and it still crashed.

Any ideas of what the heck could be happening here? I can't believe that the host computer would be overloaded, but maybe it is?

crashing with errors or freezing?

Completely freezing. I have to hold down the power button and do a hard reset.

tried running the host computer in compatibility mode for the game like for winxp. i'm clutching at straws here cause i have no idea what's causing this. computer specs are good

Quite a hard one to track down so I'll suggest some stuff to try ..

Definitely worth trying the compatibility modes Surfer suggested, or installing another version of windows in dual boot to take windows 7 out of the picture (if you have the time & disk space)

Maybe it's as simple as a faulty network cable ? though I'm not sure how this could freeze the PC it's worth eliminating. Maybe update network card drivers too, it's quick and easy

are you running 64bit windows 7 ?
Have you tried the lower spec PC as the host ?
Have you checked the technical support website for the Game ?

i can reproduce video lockup by over clocking my ATI 3870. another thing that can cause video lock is heat. clean the heat sink/fan for the processor and GPU and reset the 9800 clock to default.