This is my hardware setup:
Windows 7 PC (Gigabit Ethernet) -> 3Com Switch (LED indicate 100Mbit connection) - D-Link DIR-655 Router - 3Com Switch (LED indicate 100Mbit connection) - QNAP NAS TS-409 Turbo
However, the network monitor never exceeds 30 Mbit transfer speed, even if I copy large single files from one side to the other.
Is that normal? How can I utilize the full speed of the network? How can I find the bottleneck?
Note: I cannot reduce the number of devices in the middle since the NAS is in another room and I need both switches since there are several other devices connected to both switches. When I tested, the other devices did not any significant transfers that would affect the transfer speed significantly.