Disconnect Ethernet cables from LAN and WAN ports. If the router still restarts, then its hardware issue. Your router will have to be exchanged for a new one.
what is your downstream bandwidth?
might want to visit this thread; http://forums.smallnetbuilder.com/showthread.php?t=14142
I know this is a problem with some ISPs. No idea what the cause would be, the HW acceleration is all closed source.
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