Win 7 slow file copying to network drive - is it Win7 problem?

I was backing up files using RoboCopy from my Win7 (64-bit) home machine to a network drive mounted on an XP Prof machine and noticed it was awfully slow. A check of the Network Utilization in the Task Manager's Network tab revealed that it was clocking only 2-4% and no one was using the network except me.

When I was reading this thread seeking any solution to my problem, I never believed it was the fault of Win7. Why? When I was doing a similar operation using a Cat5e cable with my laptop, the network utilization was in excess of 98% constantly. Hence I knew it was not Win7, as blamed by the above thread nor my network.

I knew it must be hardware associated with this machine that exhibited the slowness. Thankfully experience told me not to follow the instructions posted on the Internet blindly or else I could end up in a worse shape than I began with.

It turned out the solution was simpler than many would have guessed and it was highly unusual but the signs were always there.

It was a faulty Cat5e that was used to connected this machine to the router. The cable did not exactly not broken. Only the transmit line must be hanging by the thread resulting in slow copy to the server but acceptable performance in copying from the server. What pointed me to this simple solution was the fact that I was using a totally different cable when connecting the laptop to the network.