ASUS RT-N66U Wired Issue

[Desmond Ng]

Fixed 1nos of structured LAN cable done in 2 rooms. With termination of LanPort1 in Room1 and LanPort2 in Room2.

Modem, Router and PC1 is in Room1
PC2 in Room2

Modem > LanPort1 >>> LanPort2 > PC1 or PC2 600+mbps(speedtest)

Modem > Router > LanPort1 >>> LanPort2 > PC1 or PC2 90+mbps(speedtest) PROBLEM

Modem > Router > PC1 or PC2 600+mbps(speedtest)

Only 3 lan cables were used throughout the test
Modem x1
Router x1
PC1 or PC2 x1

What is it when the router is introduced between the 2 lan points, both PCs are unable to run at gigabit speed?But when both PCs are connected directly to the router, both PCs are able to run at gigabit speed?

Any help is deeply appreciated, thanks in advance.

 

[TheManFromUncle]

Desmond, I am not sure I quite understand your query. The third setup, Modem to Router to PC1 and/or PC2 is correct, installing the modem on the WAN port. Also, what is your internet speed and are you in any way able to test speeds internally, LAN to LAN, WLAN to WLAN or WLAN to LAN?