processor speed

[Ivan Glushkov <Ivan.Glushkov@mail.desy.de>]

Hello,
I am new at the world on Linux/Debian.
Since two weeks I have Debian 3.0 with kernel 2.6.7 on my Asus M6726NW 
laptop. My question is what does this mean:

Processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 9
model name      : Intel(R) Pentium(R) M processor 1500MHz
stepping        : 5
cpu MHz         : 600.281 ???
cache size      : 1024 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr mce cx8 apic sep mtrr pge mca 
cmov pat
clflush dts acpi mmx fxsr sse sse2 tm pbe tm2 est
bogomips        : 1183.74

/proc/cpuinfo (END)

Is my processor really running on 600 MHz? And if so, any idea why?
I would be greatfull for any hint.
  
         Regards, Ivan