slow network transfer speeds

[bwanaaa]

2 pcs connected by cat 6 cable an gigabit switch (cable runs 20 feet, new netgear switch)
(opteron @3 ghz,2 gig ram, gigabit NIC on mobo, windows 7 pro 32 bit)
(core i7 920 @ 4ghz, 6 gig ram, gigabit NIC on mobo, windows 7 pro 64 bit)

8 gig file transferred from one pc to another.
Transfer starts out strong an peters out to 1.5 megabytes/s.

Removed remote differential compression on both machines.
Disabled autotuning on both machines.

Transfer starts out much stronger (~100% network utilization!) but then peters out to 3 MBs/s

It wants an hour to transfer an 8 gig file! Shouldnt this transfer be faster? How can I diagnose the problem?

iperf shows 503 Mbits/sec with an 8 k window size and transferred 601 MBytes. shouldnt this be closer to 900 Mbits/s?

well, setting the tcp buffer to 65000 gets me to 98%utilization so it seems that if i want my transfers over the LAN faster I need to manually make the window bigger every time I drag a big file from one box to the other. but for internet stuff, that window is too big. is there a way to make the buffer bigger for LAN only transfers?

 

[Fallen Kell]

Not really... welcome to the world of network tcp optimization.... You now know why the out of the box settings are never good enough for anyone since they are pretty much a compromise between latency and thru-put.