https://www.google.com/#q=does+xp+need+internet+optimization&spell=1
did you go to google search page on optimizing xp ??
http://forum.notebookreview.com/windows-os-software/56641-cable-nut.html
read the thread here on cablenut, it is a pretty old program, some reviews say it does not work on xp, and the thread above says that xp has already optimized the settings.
I have tweaked my xp, but not the internet, it seems fast enough to me, I have done some speed tests, with and without my ISP provider on the phone, and they say it is pretty good.
I have tried to see if downloads would be faster, but this is not necessarily an xp tweak as the download speed depends on where you are downloading from.
I did read through your link, I have set the registry settings and disabled the sections advised on network properties, but I will not download cablenut. It seemed very technical to me. But if you try it remember to set a restore point.
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