What model Realtek network cards? Realtek makes some good network cards but most are crap IMHO, especially with the Windows Update drivers. Install the latest drivers from the manufacturer and if needed enable flow control in the transmit (Tx) and receive (Rx) directions. See [url=http://support.microsoft.com/kb/929707]http://support.microsoft.com/kb/929707[/url] for more on the network settings.
