Is there a minimum round trip delay for FRS replication

I have a network with several remote locations. Two of these locations are in China with a round trip delay averaging a little of 300ms.

I am finding that FRS replication of for instance a new login script will replicate to all my other sites within 10-15 minutes, but to my two China sites, several hours to a day.

I seem to recall seeing something about round trip delay someplace, but I haven’t been able to find anything on the net. I am running an all Windows 2003 AD environment.