It all comes down to the speed of your modem(bps or bits per second).
Your modem has a speed of 28.8kbps or 28800 bits per second, while your
processor is running in the neighborhood of 4 MIPs or 4 million
instructions per second. Even with compression both hardware and
software with your modem, you're still only looking at a possible 115kbps
which is minimal compared to the capabilitities of your processor. There
are other items that do play a part, such as, your system bus, harddrive
speeds, wait states, but I will avoid these for fear of being flamed for
being to technical.
Hope this Helps.
Brian Deeley
bdeeley@clark.net