Probably cached in your browser.
click on these 2 gamefiles battlefield_2142_demo.exe and bfme2demo_english_final.exe and save them to your desktop, and then wait a couple of minutes then write down the transfer rates on the files that are running add them together then multiply them by 8 and you will get a truer download speed.
Remember to stop and delete the files.
i.e : 250Kbps X 8 = 2Mbps, 500Kbps X 8 = 4Mbps, 1250Kbps X 8 = 10Mbps, 2500Kbps X 8 = 20Mbps
Then add 10% to the final figure to account for any processes running on your computer.
http://www.virginmedia.com/testmyspeed/manual.php