Slow SMB transfer from Windows 7 to Server 2012 R2

[Kashim]

Hi. I'm trying to transfer large files from a Windows 7 machine to a Windows Server 2012 R2 box and I'm only getting around 45 MB/s. The entire network is on gigabit and I know that both the Windows 7 machine and the server are capable of saturating the gigabit link.

 

If I transfer a single large file to the server, I only get around 45 MB/s, but if I start a second transfer while the first is running then the total speed goes to 85-90 MB/s. Then if I start a third transfer, my total speed goes to 110-115 MB/s which is very close to the gigabit speed limit. Slow read/write speeds on either end are not an issue, the storage devices on both ends are capable of read/write speeds in excess of 300 MB/s.

 

Also, if instead of "pushing" the files to the server, I "pull" a single large file to the server (from the Windows 7 machine) then I get around 90-95 MB/s. Anyone know what could be causing this? I need to transfer a lot of large files to the server, but they must be done sequentially not in parallel and pulling them all from the server side is not an option. I need to find a way to get the full speed on individual file transfers coming from the Windows 7 box to the server.

 

The Windows 7 machine has an integrated Intel 82579V Gigabit Ethernet chip. The server has a Realtek Gigabit controller, not sure what chip. Both machines have the latest network drivers installed. I tried changing some of the advanced driver settings on the Windows 7 machine like enabling Adaptive Inter-Frame Spacing and a few others, but they seem to have no effect on transfer speeds. Any suggestions to improve transfer speeds would be greatly appreciated!