Oh, Windows 7? That does explain it. Windows TCP stack really improved in 8.1. The main change there is the auto send buffer tuning which allows automatic gr

Oh, Windows 7? That does explain it. Windows TCP stack really improved in 8.1. The main change there is the auto send buffer tuning which allows automatic growing of SNDBUF. Let me see if we can put a dirty hack^W^Wworkaround for Windows < WIN2012R2SERVER that would unconditionally set SO_SNDBUF to something like 1Mb.