Is networking slow or does Task Manager LIE?

I have one computer with Home Premium installed and another computer
with Windows XP Pro installed. Both computers use the firewall that
comes with their operating system as well as Windows Defender. Neither
of them has any anti-virus software installed. Both computers can
access the Internet and each other.

When I download from the Internet my download manager shows a download
speed of 643KB/sec which I consider very good. The Windows Task
Manager show a network utilization of about 0.5% which seems really
slow. Ditto when I transfer a large file from one machine to the
other but the network utilization doubles to about 1%.

What exactly does network utilization mean? I thought it is a
percentage of the maximum speed your system can handle? This does not
seem to be true.

Al