Help on QueryPerformanceFrequency()

[j3r3mi]

Hi all, this is my first post. Sorry if i'm asking some noob questions. I posted this help in Atom developer forum, but they refer me here. First of all, SORRY if i posted on the wrong forum.

Currently i'm working on some visual embedded system which is using Atom Z530 (1.6GHz)

My idea was to test the execution time of my algorithm on this platform.
I used the QueryPerformanceFrequency() function in "windows.h" to get the clock frequency counter for high precision.

I did a trail on a Dual Core 3.6GHz and this Atom.
Here are the results
1) 360019000 ~ 3.6GHz for the Dual core.
2.) 3579545 ~ 3.5MHz for the Atom Z530.

I understand that Atom has this SpeedStep technology. But i disabled it in BOIS and set it to use the Maximum CPU. But i still get same frequency.
May i know what am i missing out?

I'm using Visual studio 2005 pro, Windows XP Sp3

Thanks in advance!!
Jeremy

[neni · Accepted solution]

QueryPerformanceFrequency/Counter are not always using the real time "clocks" of the processor, their implementation varies between different timers in the system (and between OS versions, etc). The only thing which is guarenteed is that for given time difference (for example 1sec) the results of two quesries of QPC will correlate to the same scale of QPF. the actual frequency does not matter.