Horrible ethernet performance under mild load - SB75G2

Discussion in 'Shuttle' started by Google, Jan 7, 2004.

  1. Google

    Google Guest

    Hello everyone;

    I have a Shuttle SB75G2 XPC with the onboard Broadcom SCM5788 gigabit
    ethernet port. I have a Seagate Raptor 74G SATA drive (OS), a Wester
    Digital 200G "Drivezilla" PATA drive (storage), and I'm running
    Windows XP SP1.

    My PC is connected to a Linksys 10/100 switch (not hub in case it
    matters). I also have a mid-end Windows 2K Pro machine with an Intel
    Pro 10/100 nic connected to the Linksys. Finally I have a Redhat 9
    server with 2 Intel Pro 10/100 nics, one connected at 10Mb to the
    cablemodem, one connected to the Linksys. I'm using iptables+snat to
    masq an rfc1918 private network (the two windows machines) through the
    cablemodem via the Redhat server.

    When I'm using Newsbin Pro (4.x - registered) to suck down tons of
    binaries on usenet at 3-3.5 Mbps over my Cox cablemodem, my
    windows-to-windows file transfers slow down to about 1.5 Mbps.

    When I use the option menu in Newsbin Pro to set the bandwidth
    limitation from NONE to 500 Mbs my windows-to-windows file transfers
    speed up to about 48 Mbps.

    When I allow Newsbin Pro to download at around 1 Mbps my
    windows-to-windows transfers slow to about 8 Mbps.

    When Newsbin Pro isn't downloading, I get a windows-to-windows
    transfer of about 75 Mbps.

    My suspicion is the fact that the Broadcom gigabit chip is sharing
    IRQ15 with the IDE controller(s) the Shuttle can't handle the load
    between disk access and ethernet throughput.

    Does anyone have any ideas on how to make the Broadcom chip perform
    full speed under any load?

    Google, Jan 7, 2004
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