Is Comcast cheating on net speed tests?

JimDaGeek writes: I recently moved to Columbia, SC where I have Time Warner as my cable ISP and pay for an 8 Mbps connection and have been very happy with the service, speed and reliability. In contrast I have heard bad things about Comcast, so now that I am up in the Philadelphia PA area visiting my parents, I decided to test out the speed and reliability. For the speed test I went to the Speakeasy speed teset.

To my surprise, here are the results:

New York, NY test: 18,946 kbps up, 1,578 down<br>
Washington, DC: 15,821 kbps up, 1,559 kbps down<br>
Atlanta, GA: 11,257 kbps up, 1,552 kbps down<br>
Chicago, IL: 10,042 kbps up, 1,556 kbps down<br>
San Francisco, CA: 4,230 kbps up, 1,521 kbps down

The San Francisco, CA numbers seem much closer to the rated speed of my fathers connection. So as someone who has never used Comcast until yesterday, what is going on? I know my father is not paying for 10+ Mbps connection. Is Comcast giving priority to popular speed test sites?