Are the times of the warning the same time when your laptop might be going into a standby state or shutting down components to save power. If the warnings are being recorded when you are not using the laptop, then you might not need to worry.
When you say the connection slows, do you mean you see the rate of your connection dropping, or do you mean that sometimes getting your data takes longer? If you mean the latter, then the slow down might be caused by something outside of your network. Even if the connection drops while you are active, you probably wouldn't notice a difference in the time it takes to get your data from the Internet.You are probably just seeing the normal Internet slow downs most of us see.
If you think you have a problem on your network you can try a few things that might make a difference.
Do not be surprised if going through the above steps does not make any difference. The usual cause of slowdowns like you experience on the Internet are caused by something outside of your network and beyond your control.
Mark H
It looks like Intel PRO/1000 software (at least 14.6 and 14.7) try to switch to lower speed as part of power saver mode. On most of Cisco switches it causes renegotiation and spanning tree protocol recalculation which causes port unavailability for about 30 seconds. Driver which comes with Windows Server 2008 R2 x64 has an option which disables attempts to save power but it disappears with PROset software installation
Changing this "Feature" fixed the issue:
Error: E6400 systems Ethernet card disconnects after LCD screen turns off
Solution: Run Regedit.exe. Click on computer. From menu select edit/find. Search for SipsEnabled Change from 1 to 0. Press F3 to search for next until all are changed. Reboot
i can't find that key on my win7 x64. yet the error come up regulary.
can you provide the exact location of this key?
You do not have to use the registry editor. You can configure the SipsEnabled setting using the System Idle Power Saver(SIPS) in the Advanced tab in the device properties in Windows Device manager. If you have Intel(R) PROSet installed, then look in the Power Management tab for Reduce link speed during system idle. The screen shots below show SIPS locations for both cases. If you do not have a SIPS configuration option, then the driver for that network connection does not support SIPS in that operating system (or maybe you need to update the driver.)
Above shows SIPS property when only the base driver is installed.
Below shows SIPS property when Intel(R) PROSet for Windows Device Manager is installed.
Thanks for the tip. Works well when the user is allready using the system. But when you SYSPREP a system it removes that setting, the default setting is set back it sipsenabled=0 which is power save mode 
. So you need to load a reg file on first log on or in setup.cmd to change this to 1.
Intel should change the default to power save off.
14.7 version of the software doesn't have that option. So where's the reg key?
The driver files I have checked so far (at least in the newest versions) do indeed have SipsEnabled set to "0" by default. However, "0" is the setting for Disabled. Are you experiencing the opposite? What is your driver version and OS?
win7 x64 ultimate. driver version 11.2.19.0
morbidz,
I am guessing that you have a Intel(R) 82567LM-3 Gigabit Network Connection, right? That is different than the Intel(R) 82567LM Gigabit Network Connection. There is no SipsEnabled option for that connection in Windows 7 for Intel(R) 82567LM-3 Gigabit Network Connection.
Some network connections support System Idle Power Saver and some do not. The setting only appears for network connection and OS combinations that have support for the option. Any network connection or adapter that does not show the setting does not have support for the option or does not have support for the option in that OS.
i'm not really concerned about having that option 
i'm concerned about my card dropping the link very frequently.
it's not my wiring as i have the same machine @ work and @ home. same behaviour on both.
Again, installing PROSet 14.7 onto DQ45CB with 82567LM-3 causes network connection issues. Microsoft's driver 10.5.1.0 dated 21.10.2008 does not. All PROSets starting from 14.3 have same behavior on Windows Server 2008 R2 (tried up to 14.5 on RC and 14.6 and 14.7 on RTM)
thank you, Max! went back to v10.5.1.0 and errors stopped and more importantly media streaming to WDTV(Live) is back to normal!
I can confirm this issue (I'm using DQ45EK). After a while, 82567LM-3 drops to 10mbps, and even manually setting it to higher, the link is limited to 10 mbps. After reboot it works again with correct speed.
With Microsoft's driver it works as it should, but otherwise I'd rather use PROSet - Intel or anyone, are <14.3 PROSets stable enough or is the Microsoft's driver the recommended one?
