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CPU runs at lower than stock speed? Look here

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The Coolest

Senior Member
Joined
Jul 29, 2001
This seems like a very common problem. I see a lot of posts where people say that my cpu runs at xxxxMHz and not at yyyyMHz, after upgrading.
Well most likely thing to happen is that the motherboard sets a default FSB speed which is not the speed that the CPU is meant (by AMD) to run at.
For example. If you get a Barton 2500+ put it in and turn your comp on and only get 1100 or 1467MHz its because the stock FSB of the chip is 166, and the motherboard sets it to 100 or 133.
The CPU speed is set by 2 parameters: The FSB (Front Side Bus) speed and the CPU Multiplier, so if the default multiplier on the Barton is x11 and you're getting 1100MHz or 1467MHz, it means that you're running at either 100 or 133MHz FSB.
To fix this all you have to do is go into the BIOS and change the FSB setting to the one that the chip was meant to run at, so for the Barton it'd be 166 (166x11 = 1833MHz, the stock speed of the Barton 2500+).

Same thing can happen with a 133MHz CPU, so if you're running a 1700+ (has a x11 default multi as well) you'll only get 1100Mhz, it means that you have to set your FSB back up to 133.
 
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Great info to bad no one that need to knwo this will read it cause if they did we never would have to post this great answer to a noob problem once a day.
 
i agree and i have never had this problem but i expect that most people expect when they first boot up, that the mobo will auto detect their chip...and that's why this always comes up.....
 
Good post except for one hugs thing you missed out on, most motherboards employ either a jumper of a switch to set FSB starting points 100/133+ I recommend checking your motherboard manual to see if you are not somehow overlooking one of the above mentioned options. Having recently set up a gigabyte that refused to go over 1100 mhz instead of the barton 2500+ that was in it, so upon inspection I found a switch to select between 100/133+ upon switching the auto select worked just fine.

Just a tip.

J :cool:
 
But what if your mobo doesn't support 166 FSB? I have a Gigabyte GA-7DX+ with no multiplier adustment. And I can't find any PCI/AGP clock adjustments. Last time I tried to adjust the FSB, it wouldn't POST. I had to reset it with the jumper. Is there any software available that I can change this with?
 
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