Clock Frequency

freqclock
Hello All,

I have written a C program that basically read value from ADC , I am
reading ADC data in loop and process the data. Reading 1000 times it takes
1 min of time with default freq(405 Mhz), however If i changes the freq.
from 405 Mhz to 500 Mhz, execution time decrease 55 sec (measure using time
command) but actual time is same as 1 min(measure using stop watch). 

why?

why I am not getting difference in actual time, after increasing freq,
actual time measure using stop watch and system time must be same. but I am
getting difference in time.

Can someone please explain, what causes problem over here..., where else I
need to change in kernel, I am using 2.6.32 kernel.

Thank You for your time and consideration

regards,
freqclock