My setup: I have a PC with a Gigabyte GA-MA78S2H motherboard (Realtek Gigabit wired Ethernet on-board). I have the latest drivers (at least the latest driver for the NIC.

I'm connecting via an Edimax BR-6216Mg (again, wired connection).

For some reason I experience short periodic disconnects and reconnects. Specifically, Skype disconnects, tries to connect, succeeds after a short while; incoming SFTP sessions get dropped; using a browser, I sometime get stuck in the DNS lookup or connection to the website and a page won't load. A couple of seconds later, a reload works.

All this happens with Windows XP SP3. With Windows 7, it doesn't happen. The connection is smooth (OS is sluggish though, but never mind that).

Like I said, I updated the NIC driver. I tried reducing the MTU (used something called Dr. TCP), thinking maybe that would help, but it didn't. (I'm a bit but not super-knowledgeable about TCP parameters.) I'm guessing it's either a problem with the driver or some settings which are different between the two OSes.

ipconfig for my adapter:

Ethernet adapter Local Area Connection:

    Connection-specific DNS Suffix  . :
    Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
    Physical Address. . . . . . . . . : 00-1D-7D-E9-72-9E
    Dhcp Enabled. . . . . . . . . . . : Yes
    Autoconfiguration Enabled . . . . : Yes
    IP Address. . . . . . . . . . . . : 192.168.0.2
    Subnet Mask . . . . . . . . . . . : 255.255.255.0
    Default Gateway . . . . . . . . . : 192.168.0.254
    DHCP Server . . . . . . . . . . . : 192.168.0.254
    DNS Servers . . . . . . . . . . . : 192.117.235.235
                                        62.219.186.7
    Lease Obtained. . . . . . . . . . : Saturday, March 10, 2012 8:28:20 AM
    Lease Expires . . . . . . . . . . : Friday, January 26, 1906 2:00:04 AM