Your modem may be Retraining, Speed Shifting during the connection.

Ah, yet more Black Magic about modems. First we need to see if you are having this problem.

1. Connect to the Internet and take note of the speed reported when you connect.

2. Click on this link and start to download the file Speedtest this is a harmless image file zipped so it will give you raw Throughput of your modem connection.

3. While the file is downloading look at the Transfer Rate. Lets say for example your modem reports that you have connected at 52000 bps, you should see approximatly 5.7 KB/sec download speed on a Perfect 52000 bps connection. You will not likely see a perfect connection at any speed.

4. The Formula for what your "Perfect" Transfer Speed is:
   (Connect Speed bps ÷ 9)÷ 1000 = Transfer Speed KB/sec.
   For example (52000 ÷ by 9) = 5777.77
   (5777.77 ÷ by 1000)= 5.7 KB/sec.

5. What we are looking for is a great deviation from your "Perfect" Transfer Rate. In the above example, if your Transfer Rate is let say 4.8 KB/Sec you are doing pretty well and should leave well enough alone. If it was 2.4 KB/sec then you have some problems you may wish to address.

Solutions

1. First as always make sure you have the Latest Modem code and Drivers for your modem. Check with your computer Manufacture for Updates. I cannot Stress this enough, it is very important. You may also wish to check here 56K Modem Troubleshooting

2. When Slower is Faster. A funny thing is sometimes you can Increase your Transfer Speed, by Lowering your Connect Speed. You do this by using special Modem command Strings to LIMIT your Connect Speed. A complete write up on this topic is at 56K Limit Connect Speed

3. Now what you want to do is Limit your connect speed to some Speed. I usually start with 48000. Connect to the Internet verify I did connect at 48000 and do the Speed Test again. If all is well, then I can try the next higher speed. If not I go one Lower. On a really bad Phone line I may Disable V.90/56k and Set it to V.34/33.6. I can tell you from experience a good 33.6 connection beats a POOR 56k any day.