Win2k3 + NetXtreme: How to set the MTU?

[drizzt81]

I am running win2k3 standard on my dell SC420. It has an on-board NetXtreme 5751 GbE card. I have installed the lasted (10.24d) drivers. When right clicking the network card and selecting properties, I have a tab called advanced that has all kinds of options, however no entry to select the MTU size.

Some searching led me to believe that I can edit the registry and add a MTU DWORD entry for the adapter, which would ``force'' it to use larger MTUs. I have done this and rebooted. I am still not able to use the 7K MTUs which the other two hosts on the GbE-only network are using.

I understand that using large MTUs has little benefit, but when copying ~400GiB of data, I think I can benefit from pretty much every little bit that I can get.

-supporting data
ping Linux FS from Win2k3:

C:\Documents and Settings\Administrator.GKNET>ping -f -l 6500 192.168.3.16
Pinging 192.168.3.16 with 6500 bytes of data:
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.
Packet needs to be fragmented but DF set.

ping Windows workstation from Linux FS:

deb-serv:/fileserver# ping -c 4 -M do -s 6500 192.168.3.8
PING 192.168.3.8 (192.168.3.8) 6500(6528) bytes of data.
6508 bytes from 192.168.3.8: icmp_seq=1 ttl=128 time=3.87 ms
6508 bytes from 192.168.3.8: icmp_seq=2 ttl=128 time=0.499 ms
6508 bytes from 192.168.3.8: icmp_seq=3 ttl=128 time=0.495 ms
6508 bytes from 192.168.3.8: icmp_seq=4 ttl=128 time=0.462 ms

ping Linux FS from Windows XP Workstation:

c:\>ping -f -l 7010 192.168.3.16
Pinging 192.168.3.16 with 7010 bytes of data:
Reply from 192.168.3.16: bytes=7010 time<1ms TTL=64
Reply from 192.168.3.16: bytes=7010 time<1ms TTL=64
Reply from 192.168.3.16: bytes=7010 time<1ms TTL=64
Reply from 192.168.3.16: bytes=7010 time<1ms TTL=64
Ping statistics for 192.168.3.16:
    Packets: Sent = 4, Received = 4, Lost = 0 (0&#37; loss),

 

[Madwand]

Broadcom PCIe NICs are infamous for not supporting jumbo frames. So you can't.

 

[drizzt81]

While it is not the answer that I would have liked to read, thank you for replying so quickly.