Processor Under-Clocked?

Gallifrey

Keeper Of Traken
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Ok, something very odd has happened to my computer and I'm trying to figure out what it is, so I'm asking the clever folks here for ideas.
My processor is an AMD 2500+, which used to run at 1.83ghz. However, it's recently decided that it's going to run at 1.1ghz. As near as I've been able to learn from poking around the internet, is that the problem could be in a BIOS setting, but I haven't the faintest idea how that works and am not inclined to go poking around in there without a clue as to what to do.

Has anyone ever come across this sort of problem before, and, better yet, know how to fix it?
 
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Sounds like the CPU configuration in the BIOS reset itself to default values. That´s no big deal, it happens all the time. Find the "Clear CMOS Jumper" in case something goes wrong, learn the most important BIOS options and configure it correctly.

The CPU speed is usually set as
Frontside Bus (FSB) * multiplyer
for example 200 * 10 = 2000 MHz = 2GHz
or 166* 11 = 1826 MHz ~ 1.8 GHz

Sounds like your CPU is running at 100 MHz FSB instead of 166.

Sounds like a good time to learn about overclocking. An XP2500+ is great for this.
 
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Ok... I'm not opposed to learning how to do those things, but I have no idea where to look for a reputable source from which to learn. Any suggestions?

Not too sure about overclocking, my computer isn't exactly young anymore and I worry about pushing the poor thing too far!
 
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Just enter your BIOS by hitting the 'del' key or 'F2' (these are the two most common ones... just watch out for the message 'Hit [key] to enter setup' when you boot your system and it will tell you the exact key :) ).
Then you will usually find the CPU and multiplier settings under 'Advanced Chipset Features'. You use the cursor/arrow keys in the BIOS to navigate so check the 'Advanced Chipset Features' section. This is where you should find the front side bus settings (FSB) and the multiplier settings (ranging from something like 7 to 13 in .5 steps or something like that). As Gorath said, this is where you will need to set your FSB to 166MHz and the multiplier to 11 (11x166 = 1826MHz). It could be that the multiplier is fixed at 11 so there might not be an option for it. Then just change the FSB to 166MHz and that's it. Exit & save changes and you're done :) .

As far as overclocking is concerned, I wouldn't recommend it to an inexperienced user. For good OC'ing of an Athlon XP 2500+, you'd need:

- Good cooling.
- A board with an nForce2 chipset and preferably a certain revision of that board so it supports the 400Mhz FSB that you would be aiming for (like the Asus A7N8X-E Rev 1.1).
- Excellent, high quality DDR-400 RAM (or faster).

Then you could try to turn your XP2500+ into an XP3200+. I did that when I had a 2500+ but the fan noise (you really need good cooling) plus some minor but yet noticeable stability issues got on my nerves after a while and so I went back to 2500+ values and just bought an XP3200+ later on when the prices had come way down (paid EUR 129.00 or something like that).
 
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Fantastic, thanks! I'll give that a try. Is there a way to back things up before-hand in case I screw something up? I always like to have the maximum room for error as is possible ;)
 
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No, there isn't :) . But if you mess up the FSB/multiplier settings and overclock your system too much then the system should boot up in fail-safe mode the next time. Any decent board (like an Asus) has a "backup" function like that (auto-recovery).

In worst case, i.e. if there isn't an automatic recovery, you'd have to check how to clear the CMOS (= the BIOS chip) in your mainboard manual. This is usually done by removing the battery from the board for a couple of minutes or by setting jumpers into the 'Clear CMOS' position and then booting the system once with the jumpers in 'clear' mode (basically what happens then is that you short the CMOS). Then you power it off and turn it back on with the jumpers in the normal/default position. Your mainboard manual would have all the details. Let us hope you won't need it ;) .

The FSB and multiplier stuff is simple math, really. Just make sure you don't go beyond 166MHz FSB (which BTW is the same as 333MHz FSB... for AMD systems, the FSB like the RAM follows the principles of double data rate (DDR) and is transmitting data at the rise and at the fall of a signal instead of only the rise as normal so the "effective" clock is 333MHz) and not beyond a multiplier of 11.0x. Then you're totally on the safe side. Good luck :) .
 
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Ok, I shall endeavour to be very careful then! My motherboard is an ASUS, so in case I do make a mistake hopefully that backup feature will kick in. But if all I need to do is change a number or two, I think I can manage that without botching it!
 
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I would suggest making a list of all the current settings. Time consuming but if you are not sure about this stuff it may save you.
 
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Well it seems to have done the trick. I'll monitor the system for a while to make sure it remains consistant.
 
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