Ive got the Intel DQ67EP board with the Intel 82579LM onboard NIC. Ive got the machine running Windows7 64bit. Ive got this problem where randomly it drops from Gigabit to 10Mbps and will never negoiate back to gigabit. I can disconnect the cable, reconnect it, dont work. I can plug that same cable into another machine like my Lenovo T420 laptop, and it has no issues connecting gigabit, so I know its not the cable, or port, or Hub. However still plugged into a different port of the hub, still dont work. Plugged it into a different hub, still dont work, still keeps sitting at 10Mbps.
Ive rebooted it, still negoiates at 10Mbps. Shut the PC down, wait 1min, turn it on, still sitting at 10Mbps. So at this point dont believe its driver. I have the latest 16.5 running on the Windows.
ONLY way I can get this working is one of two ways. I have to unplug power, not just shut it down. I need to kill power from the board entirely. Wait 10secs, then plug it back in. Then upon starting up, its set to gigabit with no issues. Other way is to change a setting in Bios which when you exit/save it causes it to kill power to the board for a second. So the fact that killing power to the board fixes it, tells me its some hardware or firmware level issue, clearly not the driver.
Now to explain when it happens, I do have the machine set to sleep and wake at certain times. Most of the time it sleeps fine, wakes up fine and still sits at Gigabit. Theres no explanation on how many times it takes before it decides to go into some stuck state of only negoiating at 10Mbps. Even going into Device Manager and setting it to 100Mbps, or 1000Mbps, Half or Full duplex does nothing. It disconnects the Link and Reconnects but only sits at 10Mbps. Im normally connected via the IntelAMT via RealVNC.
Ive updated from the 0054 bios to 0055 last week so Im also on the latest Bios revision.
What causes this to get in such a stuck state that only killing power to the board fixes this?
Dixit