What FW version is currently loaded?
What region are you located?
What wireless modes are you using?
Try single mode G or N or mixed G and N on 2.4Ghz and single mode N or Mixed on 5Ghz?
Channel Width set for Auto 20/40Mhz or try 20Mhz only.
Try setting a manual Channel to a open or unused channel. 1, 6 or 11. 11 for single mode N if the channel is clear. 13 for EU regions. Try channel 48 or 149 on 5Ghz.
What security mode are you using? Preferred security is WPA-Personal. WPA2 Only.
Any 2.4Ghz or 5Ghz cordless house phones or WiFi APs near by?
Any other WiFi routers in the area? Link> Use »
www.techspot.com/downloa ··· der.html to find out. Use v3. How many?
Router Placement
Forum User - "Well I feel really dumb. After moving the router away from other electronic devices my speeds are back to normal. Just a heads up for anyone experiencing slow speeds, you might want to move it away from other electronics and see if that helps."
3-6' feet minimum safe distance between devices.
Placement on main level floor and central in the building and WELL ventilated is preferred. Not in basements or closets as building materials, or near by electronics devices could interfere or hinder good signal propagation.
It's not recommended to power down the router as routers are designed to be online all the time. You can set up some scheduling to disable the WiFi when it's not being used then have it come back on automatically.
Additional help and info here:
Router Troubleshooting Suggestions and Tips