The reason why IE has a fast number in the beginning is because it's calculating your download speed. It's based on a time clock so the first second or two is going to be way off.
As for a 56K modem, most people do not know this, but the "56K" in the 56K modem denotes the maximum UPLOAD speed. V.90 and x2 modems actually have a maximum download speed of 115.2K. This is specified in your modem's manual if you ever bought a 56K modem.
In some areas (large cities such as NY, LA, Houston, Chicago, just to name the 4 largest in the US), phone lines are digital instead of analog. In this case, you can obtain closed connections of 56K. If you are in a digital area and use a closed ISP such as AOL, ATT, Earthlink, or CompuServe, you can actually connect at 115.2K. This would give you a maximum download speed of 14.4Kbps.