What the hell is up with my CPU speed?

Miscellaneous and Personal Stuff I Must Share
1

Another unsolicited computer question. Hope someone can help a fairly inexperienced home-builder sort out some issue.

OK, so I was having some trouble with my system, namely video card issues. In the process of fixing it I noticed something weird about my computers CPU statistics.

I’ll start at the beginning. I built this computer myself about a year ago with very few issues. It went surprisingly smoothly. Now, I am pretty good at putting things together and can understand all the documentation, but I don’t have the vocabulary or familiarity with the basics to understand things like BIOS settings and CPU overclocking and Front Side Bus settings. All things considered, the experiment was a success.

Here’s the integral parts in case it relevant to the answer (I’ll get to the question in a sec).

CPU: AMD Athlon XP 2500+
MB: ASUS A7N8X Deluxe
Mem: Crucial DDR 2700 512MB
Video Card: e-GeForce FX 5200 128 MB AGP 8x
OS: Windows 2000 Pro

Ok, there we have it.

I haven’t really had too many issues sicne it’s been running and I’ve never dabbled with my BIOS settings or any of the switches and setting on the machine. I did update the BIOS using the automated application, but I didn’t change anything as result.

Finally, here’s the question:

Why does my system think I have a 1474 Mhz processor?

Looking at my System Information it lists this as the speed. I d/led a AMD CPUInfo application that confirms this, identifying the CPU as an AMD Athlon XP 1900+.

The CPU I bought was factory sealed from a reputable store. I’m thinking this is something screwy with my settings and not a mislabeled chip, though if it is OI want to learn how to solve that.

I think that these CPU readings aren’t read directly off the chip and are actually found by looking at the speeds the processor is operating at. Is this right?

Is this screwed up because I never specifically set up my BIOS for thisc hip assuming that it’d be auto detected? Is so, how to I fix it? Do you need to set up the clocking for the chip when you install it?

If its not a setting/configuration issue how can I figure out what the isue is and if I need to bitch about getting screwed on a CPU?

Hope you folks can help, thanks.

2

Yep, you need to go into your BIOS and check it out.

If you built the CPU yourself, you should have the MB manuals?
There should be some instructions on installing your CPU.

Failing that, there are a number of little programs that can measure your cpu speed. Just google for those.

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First off, crap…this was intended for GQ…if a mod wants to move it, feel free.

Secondly, thanks. The MB did come with docs, but they were really only for the physical install. Nothing about setting up the BIOS and overclocking stuff. Of course the physical install was the part I could handle.

Also, I already have tools to measure my speed, thats what precipitated this post, sorry if I wasn;t clear. What I need to know if the info displayed tells me what speeds my system is set to run at or what model the chip is. My understanding as of now indicated that is the former. If thats correct, I need instruction on how to set up my BIOS (and maybe switches on my MB?) to run at the intended speeds.

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Depending on your motherboard, you need to adjust the Front Side Bus speed or the CPU Ratio in the BIOS. Your motherboards manual should have specifics - if not, check the website of the manufacturer for support/manual download.

5

Yep. For some reason, the last couple Athlon systems I built defaulted to lower than spec bus speeds. In your case, the Athlon XP 2500+ has an 11x clock multiplier, and is intended to run on a 166MHz bus. Your bus is running at 1474/11, or 133 MHz.

I’m not familiar with that particular motherboard, but there will either be a jumper setting, or more likely a BIOS screen where you can set the proper (166MHz) speed-- check your manual for specifics. Good luck!

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I’ve seen the Bus setting and you’re right that it’s set lower than 166Mhz right now. I’m going to reboot in a little bit and try changing this. Its also set at a multiplier of 11, which I’m pretty sure is the correct setting.

I’ve seen alot of talk about the multipliers and overclocking in my research and I have to confess to being a little lost on how all thes things impact one another.

Could you explain these terms for me and tell me how changing them changes the “speed” of the CPU?

7

I set the Bus speed to 166Mhz and now the System Info displays what it should. Thanks.

Still curious what the story is with those items and how they affect the system. Anyone want to offer a crash course in overclocking and the terms for me?

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Basically, the FSB speed is how fast the CPU can “talk to” the northbridge chip on the motherboard, which connects to the memory. Note that modern systems use double or quad pumping (basically moving 2 or 4 bits at the same time) to double or quadrouble the effective FSB. The AthlonXP system uses a double pumped bus, so your processor is effectively talking to the rest of your system at 166mhz x2 = 333mhz. You said you have PC2700 RAM, which supports running at that same (2 x 166mhz) speed.

Now, as you have found out, the clockspeed of a processor is the result of the multiplier x FSB speed. If you push either of these higher, then your clock speed will go up. Note however that most AthlonXP’s have a lock multiplier - yours probably can’t go higher than 11. But many people with the AthlonXP 2500’s have been able to set the FSB all the way up to 200mhz, giving them a clockspeed of 2.2ghz, a nice increase. You probably won’t be able to go that far, as you have PC2700 RAM; RAM speed is connected to the FSB speed usually, and as I mentioned before your RAM is running at its maximum rated speed right now.

You still will likely be able to get a small increase though - just move the FSB speed up a couple mhz at a time, then run something CPU intensive, make sure it doesn’t cause any errors, and then repeat.

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This is known as “Nigel Tufnel Syndrome”.