Help with wired connection from RTN-66W to WRT54g ddwrt.

Hello all. New to networking. Got a RTN-66w 192.168.1.1 in the basement for the kids. Wireless in upstairs back bedroom was slow so I ran a wire thru the floor and tired to connect my ddwrt WRT54g 192.168.1.2. Initially connects at 48-54 then drops down to below 10 mbps. According to my cell phone app.

DHCP server disabled on Linksys. Modem - RTN-66w - switch - Linksys Lan port is how my setup is.

Any comments would be appreciated.
Rick