Thanks, the status page indicates Hardware A4, Firmware 1.21.
No password requirements on the old router. The way that the ADSL modem was setup was (back then and the one time in the many years I have had to switch to a new modem) by connecting it directly to one of the computers and doing all the settings including user account and password. Then the modem was disconnected from the one computer and "inserted" into the network. In the current configuration this means plugging it into the internet port of the DIR-655. This is the same way in which it was connected to the Netgear WGT624 (V3.0 I believe it was).
MTU not sure but I do not ever recall having to change anything on the old router, it was simply a plug and play operation. To the best of my knowledge (fuzzy on this because it has been a number of years, but I may try it now if the router gives issues until I find a suitable replacement locally) before the Netgear I was simply plugging the modem's Ethernet cable into one of the ports on a 10/100 and it worked without any issues of course sans the wireless access. But, if you think that this is something that the DIR-655 needs to operate properly then I am willing to change it as needed.
Upon clicking on a web page it seems slow to come up with the initial page. Browsing from there on is so so. Where the issue with the lag/stops/freezes is noticed is with the online games where the "action" freezes for 1-3 seconds.
It was a straight swap operation. Used the old cables, even plugged them on the same ports I was using before. That is, the only things connected to the Netgear were: modem cable, a gigabyte switch on port 2, and a Netgear Powerline Adapter on Port4.
Thanks again.