That is the actual speed of your processor 1.54 ghz.
Due to the specifications of the Athlon XP's, the "New" way to describe the speed is to relate it to the equivilent Intel speed. So, a 1.54 Athlon XP hs, potentially, the same speed in terms of calculations etc as a 1.8Ghz intel CPU.
Intel still lead the way in terms of "real" speed, but by the very nature of the Athlons design, it can compete IN SOME RESPECTS with a faster Intel chip.
Wheter this is justified or not is a matter of personal choice, but watch out for the new "Barton" core Athlons arriving soon, should be interesting!