As WAN bandwidths increase default network settings in older operating systems are less and less able to efficiently use the network.
A description of the problem with high bandwidth-delay product networks (also known as the long fat pipe problem) can be found here: http://www.psc.edu/networking/projects/tcptune/
Recent Linux releases do a good job of automatically enabling large windows and selective ACKs allowing better performance out of the box; however I have not seen any data on how recent Windows (or OSX) releases perform out of the box.
Does anyone know what the defaults for enhancements such as receive window size, window scaling and selective ACKs are in Windows 7?
As a secondary point of interest I would also like to know how Vista and recent OSX releases behave.