To be honest I've had no issues whatsover with the server tool.
Browser should not get capped out because of the tool alone, this sound like a Router/Modem issue, NIC or Anti-Virus medling issue.
as a Router should at all times be able to balance data based on priority-amount of connections, and atleast mine never allows any connection use all bandwidth unless it is the only requesting one(well... except if it is Steam in which case I've got a special priority rule to put everything else on hold except of a few other programs like skype).
Another thing might be a connection limit on windows.
either try this
https://social.technet.microsoft.com/For...networking
or
http://www.speedguide.net/downloads.php
on optimal settings
3.0.8 for (versions up to Windows 7/2008 Server)
v4.0.0 Beta(Windows 8, 2012 Server, and Windows 10) ) - not sure if this one works for Win7.
for linux I don't think there is such default limitations.