Extremely Slow Download Speeds (Less than 0.5Mbps)

Hello,

I have been paying for the 150Mbps Internet package from Cox for over 2 years now with generally very good speeds of ~90Mpbs download and 50Mbps upload. However in the past week my download speed has dropped to 0.5 to 3 Mbps. Modem/router resets returns the speed to ~20Mbps for about a minute.

I am using a Linksys E1000 with no trouble for the past two years until now.

I've tried doing a factory reset of the router without much luck. I have also tried turning off WMM, switching channels and channel widths without any luck.

Changing the network mode from "Mixed" to "Wireless-G Only" improved the speed to a stable ~4 Mbps.

Throughout all this the upload speed is still sitting at a comfortable ~30-40 Mbps.

Any help on this would be very much appreciated.

Thank you,

-Arnold

Edit more information: these speeds are when using a wired connection to the router. When using wireless, the speed drops back down to ~1Mbps. When connecting directly to the modem I get the normal speeds of 70+ Mbps.