File corrupted after transfer through 1 gigabit network.?

Sounds like you are over driving the cache used for the transfer. That is quite fast for a transfer and you would need a fast processor, lots of cache, and high speed disk access for it to work. The only other thing is have both set up for larger buffers in the advanced tab of properties, and some sort of ACK/NACK which will slow down the transfer rate. Checksum will do an after transfer verification of packets and again slow down true data transfer rate.