100/100 without 3500L, 50/50 with 3500L, LAN

Hey you out there!

Just bought this router cus of all good reviews around the net.

Updated to dd-wrt and the to the newest tomat:

Tomato Firmware v1.28.2453 MIPSR2-Toastman K26 USB VPN-BT

Now to the problem. I checked on my pc and got around 50/50 mbit on some speedtests

so I took my laptop and tested directly on the fiberconverter.

There I get 91/91mbit (with same cable as the router has as wancable).

After that i tested with 2 different cables behind the router and i get around 50/50mbit with both of them.

So, the router/firmware is my problem. Do anyone of u have any suggestions on how to tweak my settings or do u recommend changing to another firmware/version?

I use my network for download/upload, gaming, streaming to my htpc and wireless connection to my laptop.

Im quite new to this so be kind :)

Regards,

Honty