This helped me and I am playing MP with 4 people in earth huge
Out of Sync Errors Unnoticed
The problem was that there emerged lots of out of sync errors early in the game. The worst thing was that it is not always noticeable that out of sync occurs. After some time, you see different things than other players. We play one very fast computer, two „normal“ computers and a slow laptop. It seems that the different speeds at which the computers are able to start a new turn cause frequent out of sync errors.
Mitigation 1
The idea is to slow down the loading of the turn at the fast computers. This is done in CivilizationIV.ini an efficient way by adding logging to the game. To slow down the fastest computer the most, please set the following in CivilizationIV.ini:
; Create a dump file if the application crashes
GenerateCrashDumps = 1
; Enable the logging system
LoggingEnabled = 1
; Enable synchronization logging
SynchLog = 1
; Overwrite old network and message logs
OverwriteLogs = 1
; Enable rand event logging
RandLog = 1
; Enable message logging
MessageLog = 1
We started by setting this to all computers and almost all out of sync immediately disappeared. At a later stage, as computers get slower, try to deactivate some of the logging options to speed up the slowest computer. The goal is that all computer finish turns with as little difference as possible.
Out of Sync With Red, Blinking Message
Usually, at the beginning oft he turns, one computer takes pretty long to finish and then, an out of sync occurs.
Mitigation 1
Like above, activate the logs
Mitigation 2
Restart all computers. Usually, out of sync happens very irregular. Some times it happens four times within an hour and then four hours not. Restarting all computers seem to help here.
Mitigation 3
In case the OOS seems to occur due to one of the slower computers, change or reduce the graphics resolution. Some resolutions do not seem to work very well on all computers. Also in windowed mode, the OOS still occur. Try another resolution. In the worst case, use the lowest possible resolution.
Timeout of Turn Loading
If you play with a really slow computer, it is the last to start the new turn. There seems to be a timeout, which causes the connection to break after some time.
Mitigation 1
If logging is on due to sync errors, deactive some of the loggers to see an increase in starting speed.
Mitigation 2
Buy a new and faster computer. Thr 10y old game requires more resources than many new games.