It’s a registry changes indeed. The reason is clear: increase network speed. We have to trust TR that it makes a difference. Do we trust TR?
I googled it with IRPSTACKSIZE SITE:MICROSOFT.COM and it seems to be mainly or only useful in big servers with old OS’es in a LAN. I don’t think that somebody saying “I have a 64 bit OS” means he is managing a big server with an old OS in a corporate data center.
With other searches I saw a lot of “in theory”, just as in the TR article.
So my suggestion is to do nothing. I really wonder why the article was written and published. It seems rather low-quality.
And, indeed, I shouldn’t use a 64 bit value (QWord).
There are so many outdated articles now that I can’t tell you if it applies today or not and whether it applies to your system.
This needs to be written: You must not test it against the Internet and take the results as gospel. As a seasoned networker you know why.
If you do test it must be on your network and a controlled setup. But network speeds are well, you didn’t reveal what the issue was. FOR EXAMPLE many complain about the file copy speed on Windows Explorer. That is NOT caused by this registry setting. It’s just something Windows Explorer is bad at. Fix? I use FTP and other apps for file copies when I want to get it for move faster.