Comment I call shenanigans (Score 1, Insightful) 515
To be perfectly honest, there is probably no study out there performed by a reputable research company that can show the network stack in Linux is THIS MUCH faster than the Windows network stack.
In fact, I would be willing to be the driver on the Compaq running windows for the network card is the compaq-provider driver and is rather stale, or even better the NIC may be a different revision than the one in the other compaq running Linux. Also, if the download speed test was performed in Windows first, chances are that Comcast had the files cached for a quicker download if the tests were performed back to back.
There are too many variables to warrant this post even being displayed, and there are no whitepapers out there that will back this performance difference.