I know, it's obvious but it had never affected performance before.
I have my DGL-4500 on a wire rack behind my LCD TV. I was getting slower DL speeds for some reason and decided to just raise the router about a foot higher and was able to prop it up and have it rest on the top of the TV (doesn't block any of the screen).
Wow, dudes, just doing that got my DL speeds back to where they were and increased the stability of my wifi signal. It used to jump from 130MBPS to 104, to 72, etc. Now, it's stable at 270-300. I never really had an issue before with it behind the TV, which is why I kept it there but something has changed as of late.
Just throwing this out there for any of you who might be experiencing connectivity or DL speed issues.