I have absolutely horrible transfer speed on a new gigabit switch with DC Server 2012 R2 running Essentials.  I made the following change and rebooted after even forcing a GP update:  
Open up Group Policy Editor, and right-click-and-edit Default Domain Controller Policy.  Go to Computer Configuration/Policies/Windows Settings/Security Settings/Local Policies/Security Options, and set Domain member: Digitally encrypt or sign secure channel data (always) and Microsoft network server: Digitally sign communications (always) to Disabled.  

The server has two GB Nics in bridge mode in the switch, and the lan speeds are horrible: a 95 MB folder is transferring at less than 89 KB, and even slows.  

All clients are Windows 7 Pro.  

Any other ideas than just this change?  Maybe a difference with Server 2012 R2?

One clue: I can pull a 16 GB PST file from a client experiencing this issue with no delay, but if I attempt to send the file it fails.  I am using the c$ share on the client.  Could this just be wiring in the cable and bad receive pairs?  

• Edited by wosully Monday, February 17, 2014 2:13 PM

Hello,

The following KB is worth a try:

Information about the TCP Chimney Offload, Receive Side Scaling, and Network Direct Memory Access features in Windows Server 2008

http://support.microsoft.com/kb/951037

Similar thread:

Slow Network Write Speeds via SMB & CIFS

http://social.technet.microsoft.com/Forums/en-US/46898c7f-92e0-4c99-98d2-18a7458a7d2d/slow-network-write-speeds-via-smb-cifs?forum=winserverfiles

Hope this helps.

Thanks, I was reading that!  Just resolved it: it was an issue with the Broadcom Extreme Network cards.  They are onboard the board and installed with the OS when I installed it, but had to change the default settings as follows, under the advanced tab of the drivers:

Under the advanced tab, offloading features that needed to be disabled:

Ipv4 checksum offload largesend offload V2(ipv4) largesend offload V2(ipv6) Vm queues TCP Checksum offload (ipv4) TCP checksum offload (ipv6) Udp checksum offload (ipv4) Udp checksum offload (ipv6)
 

• Marked as answer by wosully Tuesday, February 18, 2014 2:37 PM

Thanks! This helped for Dell PowerEdge running Windows Server 2012 R2 with Broadcom cards.

• Proposed as answer by abc.com Wednesday, July 16, 2014 10:35 AM

Dell PowerEdge with 2012 R2 here as well, but I don't have ipv4 checksum offload.. I do have all the others.

I also have ARP Offload and NS Offload, but it's correct to leave those two enabled, yes?

Thanks for the answer wosully. You saved our life here extremely frustrated what did not we troubleshoot PC, switch, Router.

You are welcome.  I know how frustrating this can be.  Glad I could help.  

Hi wosully

im doinng exactly instruction u given by disable gpo & offloading features, but the issue still presist :(

it's anything that i must do with?

Please advise.

Thank you