Gigabit network bottleneck

hihi. just wondering about a gigabit networking issue.

some1 asked me a while back and i don't have an answer.

a gigabit network between 2 dual-core systems with linksys gigabit nics, direct CAT-6 cross cable.

the transfer rate is maxed at around 200-300mbps, even with jumbo frame enabled. can't remember exact figure.

benchmark with iperf.

where are bottlenecks?

thx in advance :)
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More about gigabit network bottleneck
  1. Check disk fragmentation and Anti-virus settings. Let me know if that helps, also see if you have IPv6 running on both machines.
  2. IPv6 not used. just IP4.

    On clean install XP SP3.

    Not sure about AV. I think it was NOD32.

    Non-server or workstation class motherboard with only 32bit PCI. Standard desktop boards on both PCs.

    thx for reply.
  3. Disk read/write access could be an issue. If in RAID-0 it may help a little.

    Within Windows you can use the built-in Perf monitor to check things like CPU Utilization, Network Utilization, Disk Read/Write (IO) times.
  4. My suspicion is somewhere along the bus, board or hdd IO throughput.

    32bit PCI technically should be sufficient to handle that speed.

    This question has been bugging me for a while. so i guess i'll just have to setup actual test platforms.

    thx for the suggestions.
  5. It's the BUS IO.
  6. It is a mystery bugging me for months...I have two new Win7 laptops hardwired via cat6 and the max transfer speed I am getting is 20Mbps. Where is the bottleneck ..could it be the HD I/O speed?
  7. I can't say my suggestions is valid for everyone, but my suspicions center around the 32bit PCI bus and data pathways.

    I used RAM-to-RAM benchmarking without any hard disk, it's around 30Mbps. Occasionally maybe 40 but cannot sustain at that level. Tried Jumbo frames as well.

    I only got a single 64bit PCI Bus system waiting for another 1 coming in a month or so, and didn't have time to do more tests.

    What i want to do is test with PCI-Express Gigabit NICs.

    The limitation problem is on the Board.
  8. It's not the Cable. I got Cat6 STP running around my house :)

    It's not solely some Registry or MTU issues.

    Hard Disk can be a problem, but not significant enuf.
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