Slow Ethernet/LAN data throughput

I found this issue really mind boggling as I have never encountered it before.

Other computer can copy data from me at the very acceptable speed 9~11MB/s.
However, when I copy from others. it's going at 50~150kB/s. Now, here's the weird thing, if I went to Windows explorer and browse say C:\ and start spamming F5 (Refresh), it will then copy at 9~11MB/s. When I stop spamming F5, it drops back down to 50~150kB/s again.
I also decided to try watching Divx stored on the local drive on AA1 while copy. It was better, 3~5MB/s

I am doing these copy connected to the mains.
I also thought it might've been power management for the LAN, so I also unchecked "Allow the computer to turn off this device to save power", but not change.
I have tried this through a router and direct PC connection through crossover cable as well.

Have anyone encounter this perculiar behaviour or have a solution for it? or what else I could try?

 

Do also note that such behaviour is not exhibited on the wireless LAN connection.

 

Found the thread that exhibit the same problem I have been experiencing. Guess I'm not alone in this.
viewtopic.php?f=34&t=1026

 

I have exactly same problem. Its going REALLY slow but i dont mind atm. But it would be nice if i could get a bit faster ethernet/lan transfer