Processor losing MHz?


OSNN Junior Addict
My operating system is Windows XP Home SP1. The processor I'm using is an AMD Athlon XP 1800+ on a mobo with a VIA KM266 chipset. The spec sheet for my processor says that it's clock speed is 1533 MHz. When I right click My Computer, it says 1.53 GHz along with my 512 MB RAM. However, when I view system info, or use any hardware monitoring programs, it says my processors current speed is 1529 MHz, and that's a stable reading. When I boot my computer, BIOS says that it's clockspeed is 1533 MHz.

Did I actually lose 4 MHz, was AMD's spec sheet just rounded up, or is there a bug in Windows XP that could say this?

(And no, I've never attempted overclocking or any modifications, the processor never went above 46 C as the machine would warn me, and if it hit 50 C it would reboot. So it's not like the processor was "abused").

Thanks for your help / info. :)


F@H - Is it in you?
Staff member
Political User
minor fluctuations can and do occur during operation... allow a little leeway :)

its not going to operate @ exactly the clock speed advertised... a lot like hdd's and their advertised space :cool: cept clock speeds can fluctuate...


OSNN Junior Addict
Yeah I figured, but why does my BIOS and the spec sheet label it as 1533 MHz? Why not 1529 and just say its 1.53 GHz?

Oh well. It's not like 4 MHz makes a whole lot of difference, I was just curious. :)


OSNN Veteran Addict
also depends on the chip as there are going to be small minor manufacturing flaws which will slightly alter the clock speed, but its still within the tolerances that the manufacturers set for them


OSNN Junior Addict
I've just gotten another "clue".

Maybe it's motherboard related? My system clock is 133 MHz, and my multiplier is set at 11.5. (clock * multiplier = speed) so it comes out to 1529.5, exactly what all my programs say. I know when I increase system clock speed (motherboard has 1MHz Stepping), the BIOS speed matches whatever program I'm using says, so everything is fine then.

Maybe it's just a motherboard setback?

EDIT: I've also noticed (when comparing my processor spec to many other peoples' with the same program and same processor) that their Bus speed is 266.59 MHz, while mine is 266.05. Their system clock is 133.30 MHz, mine is 133.02.

Any clue why my clock is running 0.28 MHz slower (may not seem like much, but I'm just wondering if my processor has a defect because I swore it said 1.533 GHz in system info before.)

Could it be power supply related or something? lol sorry for all this bickering over 4 MHz, but I am a perfectionist, sadly. :eek:


OSNN Addict
You shouldnt worry too much about the variation. Its to be expected with all hardware.

My CPU was sold at a speed of 1333MHz but it runs at 1337MHz and my CD-RW drive reads about less than 40x and writes over 16x, up to 18x according to Easy CD Creator.

Your system is fine, I have a friend who also has an XP1800 and his clock speed is lower than specified.

Like NetRyder said, they are advertised at a common speed. I have two 80GB hard drives: one at 81GB and the other at 78GB. Its normal.


OSNN Junior Addict
I think it may be the motherboard, and this is the last time I'm going to bring up my processor speed, I swear, lol...

Reason being, the CPU Voltage & Frequency chart in my motherboards (AOpen MK77MII) has some core frequencies to the thousandths decimal ( but most of them just go to the hundreths (x.xx). Mine is listed in the hundreths, for example:

AthlonXP 1800+ | 1.53 GHz | 266 MHz | 11.5x

And a different model number, for instance an Athlon XP 2000+

AthlonXP 2000+ | 1.667 GHz | 266 MHz | 12.5x

So it looks like the motherboard manufacturer did slightly underclock it on purpose, no?


OSNN Addict
Its nothing to worry about. Its common for hardware to vary speeds. You should only worry if its a big gap between the selling speed and the actual speed.

As for the thing about the core speeds, Intel does the same:

Pentium 4 2.8GHz 533Fsb
Pentium 4 2.667Ghz 533Fsb

Dont fret about minor loss in speeds or even increase.

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