Windows 7: what's Win7 Limit on file transfer via X-ethernet ???

My setup is somewhat complex to explain it in full and it would take more then .... to explain....
In simple
1Gb link per computer with 2-3 computers form a switch
Windows 7 Pro / Ult /Home Pre
The question that i have what's limit on file transfer via ethernet from win to win
Cause i tried 1GB and it does, i tried 2GB and it closes connection(s)/drops it
2nd question does anyone know how to bypass it via REG or GPolicy or ? instead of joining AD for just a large file transfer and then disjoining it

when i do it with *inux for file @ 3GB-6GB it would pass trough the same switch no drops what so ever
same goes for W2k8R2 Domain machines
I have tried different ports as well as a switch




so my conclusion is "SO FAR" it's base on workgroup either one belong too or not, dictates files size transfer per 1 seating


So what is ???
how to bypass ???

There's NO limit. Try to test computerA to ComputerB, ComputerA to Computer D etc.
Is problem on ONE system only? Only when copying file from that machine to another machine? Only when copying file to that machine from another machine?

I tried with 3 different ones and it still does that