I think we've gone around (in the past) on why the speeds posted above are great whilst everyone else is lagging behind.
Not any really firm ideas. I am not doing anything fancy here that would explain it. It's a standard image like any other with very basic settings. My desktop and laptop are 5 and 7 years old, respectively, and the NICs are cheap. So, I'd expect anyone who has two 5-year-old machines with Gbe NICs to be able to duplicate this setup and these speeds.
Although I can "max out" the network interface(s) it's still basically working in the limits of what the CPU can push around. It's possible real life factors like latency play a part. I'm not sure I have a correct mental model on how latency would affect such a system.
Are we seeing the difference between wired and wireless?