Problem Connecting Mac to PC directly via Gigabit Ethernet - Limited to 100 Mbit/s

Hi,

As the thread title says.

I've connected my Mac (see sig) to my PC (see sig) directly via Cat6 ethernet cable and I use RealVNC to remotely access the PC. The problem is that the connection is limited to 100Mbit/s, specifically 100baseTX, full-duplex, flow-control, MTU standard (1500). Both the Mac and PC are gigabit-capable.

I have tried to connect both devices by manually configuring gigabit rather than auto negotiation at both ends but to no avail, updated the ethernet network PCI card driver on the PC-end, attempted to repair the local area connection and fiddled around with the network settings on both Mac and PC with, again, no solution.

Where am I going wrong? I'm pulling my hair out trying to figure out why it's not working. Can anyone offer me any suggestions on what could be at fault?

Your help would be most appreciated. :)
4 answers Last reply
More about problem connecting mac directly gigabit ethernet limited 100 mbit
  1. Have you tried another cable? (although, from experience, it's incredibly hard to screw up crimping RJ45s so they work, but only slowly).

    Are you sure that both support gigabit? The PC looks somewhat on the old side, though that's subjective.

    What happens if you run it through an ethernet switch?
    e.g. Mac <---> Switch <---> PC
    No need to connect anything else, but they could just be unhappy.

    Other thing is crossover/straight-through. Have you tried both?
  2. Someone Somewhere said:
    Have you tried another cable? (although, from experience, it's incredibly hard to screw up crimping RJ45s so they work, but only slowly).

    Are you sure that both support gigabit? The PC looks somewhat on the old side, though that's subjective.

    What happens if you run it through an ethernet switch?
    e.g. Mac <---> Switch <---> PC
    No need to connect anything else, but they could just be unhappy.

    Other thing is crossover/straight-through. Have you tried both?

    Thanks for replying. :)

    Yeah, I've tried Cat5, Cat5e and Cat6 cables and replicated the same results.

    The mac supports gigabit (see HERE) and the PCI card definitely supports gigabit.

    The PC is on the old side. Read THIS and THIS for why I'm networking between Mac and PC.

    I don't have an ethernet switch or easy access to one. I do have an wireless modem router but that only has 4x 10/100 ports.

    Forgive my ignorance: what's crossover/straight-through?
  3. http://en.wikipedia.org/wiki/Ethernet_crossover_cable
    Sort of a shot in the dark - I can't imagine either not having automatic NIC/NIC-X detection.

    Are any of the pins in the sockets bent/broken? Apparently 1000BASE-T uses all four pairs, while earlier versions only used two.
  4. I've inspected the sockets and there appears to be no damage to the pins.

    EDIT:
    FYI the ethernet PCI card is made by a Chinese company called JCG. You can find all the specs on the eBay page where I bought it. According to Device Manager the model name is Realtek RTL8169/8110 Family Gigabit Ethernet NIC and the driver version is 5.719.325.2009.
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