Ok, this may sound odd and/or may not make much sense, but if you are willing to work with me here I will answer any questions needed.
During high bandwidth usage, my internet drops, not my router, BUT all the other devices on my network still connect to the internet (no problems). I can still connect to the D-link setup (192.168.blah.blah) with no issues. If use high bandwidth on any machine in my house (5 total) the internet will drop on that machine only.
This is what I have connected:
2 laptops (wireless)
1 PS3 (not always on, wireless)
2 Xbox 360's (not always on, wireless)
1 iPod (wireless obviously)
I have a basic configuration on my router besides the typical wifi passwords and some port forwarding.
DIR-628
Firmware: 1.25NA
Hardware: A2