Please revisit RealAudio Web page

One very interesting observation is that the time lag (as best as
can be timed using phone/email/irc) is essentially the same whether
one is using TCP or UDP as the Preferences-selected transport.

Failure modes are different: TCP causes a halt and resume effect,
UDP causes "noisy choppy" degradation. A packet trace at the
transmitter end would be neat (hint Scott hint), to compare whether
the UDP transport is "gentle" compared to the TCP transport.