Realtek.... I'm not the only one experiencing this. It's a pretty major issue since these machines are new and stock out of box. I uninstalled the McAfee Suite that came with it. Screw me if I have to perform a system restore prior.
I doubt the article linked is going to help. Lenovo, M$, they all want to charge me $$ for:
A new Win7 machine that connects correctly to a WinXP box with full wire speed but not to another Win7 machine.
I'm an MCSE (NT4 and Win2K), CCNP. I already paid M$ to look into it and 4 hours and they don't know. Internet speed is fine by the way. This is one of M$'s magic protocols gone running amuck.
FTP/HTTP/Old School CIFS works juuuuust fine.
Also the fact last week I had to kill TCP/UDP offload features on a Host NIC to get Windows XP compatibility mode's networking running full speed just further enhanced my belief that we are making the right move in 2013 to totally dump M$.
As a business user I can't stand M$ anymore. As a network engineer I'm not recommending their solutions any more.