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CPU Voltage reporting anomaly - please help!

Last response: in Overclocking
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May 31, 2006 8:33:56 AM

I'm running an AMD 64 3000+ on an Asus Sli board, and have been playing around with overclocking the chip.

I have had to increase voltages to get to speeds I desire, however there seems to be an anomaly between the voltage reported in windows through the Asus utility, and the voltage which I set through the BIOS.

The voltage reported in windows is about 0.4V less than what I have set in the BIOS. This is clearly very substantial. Now what I'd like to know, is do I take the BIOS reading or the windows reading, and what voltage is considered reasonably 'safe' for this chip? I have a water cooling setup and under load the chip (At 2180mhz) is running at no more than 39 deg C.

Thanks!
May 31, 2006 9:05:49 AM

Only 100% safe voltage is the default voltage, even if doesn't result in excess heat.

Most PC voltages have a tollerance of +/-5% so overvolting by 5% is safe enough. Parts should tollerate +5% extra. 11% is as far as I risked it with my AMD 64 3000.

I push my system as far as it will go at about 10% overvolting while still passing all my stability tests.

Then I take it down one notch and then find the lowest voltage that yields a 100% stable system at that speed.

Plus I boot a bit underclocked (because I can't change memory & HT ratios in Windows) and then cranked up the voltages and speeds before launching a game and cranked them down afterwards.

I guess I am a real overclocking whimp. But I never damaged anything either.

If I could afford a new MB/CPU every six months I would probably have a waist high stack of dead part.

No actually I would probably move to a bigger apparment, or eat an fine resturants more often and keep overclocking like a real wimp.

I spent 120 hours gaming at 5.5% so I guess that is safe.

---
Try setting it to normal and see what the reading says. If its still low then the reading is off. If you see the right voltage then the BIOS is probably overrignd your choice to protect you from yourself while tricking you into thinking you have a feature which you don't.
May 31, 2006 9:33:40 AM

Quote:
If you're looking at CPU-Z it's reading the wrong sensor.
You can change which sensor to read in the .ini


Could you tell me how to do this please? CPU-Z reports the same voltage as the Asus utility.

And Codesmith, thanks for your post. What voltage were you running your 3000+ at?
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May 31, 2006 10:44:58 AM

Look at their site and look for Configuration file:

http://www.cpuid.org/cpuz.php

Basically it is your cpuz.ini configuration.

Quote:
VCore Switches between the different voltages reported by the sensor chip. If 0 (default value) reports a wrong vcore, try 1, 2 and so on.


Not sure if that helps, but if Asus probe is say thing same thing, I guess it is looking at the right one.
May 31, 2006 11:07:47 AM

Quote:
Look at their site and look for Configuration file:

http://www.cpuid.org/cpuz.php

Basically it is your cpuz.ini configuration.

VCore Switches between the different voltages reported by the sensor chip. If 0 (default value) reports a wrong vcore, try 1, 2 and so on.


Not sure if that helps, but if Asus probe is say thing same thing, I guess it is looking at the right one.


Well I agree with you :-D

But ASUS Probe and CPU-Z sometimes read the wrong sensor and sensors sometimes report the wrong voltage.

If the temps are reasonable, which they are it should be fine.
May 31, 2006 12:16:21 PM

Quote:
Look at their site and look for Configuration file:

http://www.cpuid.org/cpuz.php

Basically it is your cpuz.ini configuration.

VCore Switches between the different voltages reported by the sensor chip. If 0 (default value) reports a wrong vcore, try 1, 2 and so on.


Not sure if that helps, but if Asus probe is say thing same thing, I guess it is looking at the right one.


Well I agree with you :-D

But ASUS Probe and CPU-Z sometimes read the wrong sensor and sensors sometimes report the wrong voltage.

If the temps are reasonable, which they are it should be fine.

I don't think the temps are really ever going to be 'not' fine, with this watercooling. So I really need to know whether to trust the voltages I have set in the BIOS or the voltages being reported in Windows. Is there somewhere on the motherboard I can test the voltages with a multimeter?
May 31, 2006 12:35:29 PM

Quote:
Look at their site and look for Configuration file:

http://www.cpuid.org/cpuz.php

Basically it is your cpuz.ini configuration.

VCore Switches between the different voltages reported by the sensor chip. If 0 (default value) reports a wrong vcore, try 1, 2 and so on.


Not sure if that helps, but if Asus probe is say thing same thing, I guess it is looking at the right one.


Well I agree with you :-D

But ASUS Probe and CPU-Z sometimes read the wrong sensor and sensors sometimes report the wrong voltage.

If the temps are reasonable, which they are it should be fine.

I don't think the temps are really ever going to be 'not' fine, with this watercooling. So I really need to know whether to trust the voltages I have set in the BIOS or the voltages being reported in Windows. Is there somewhere on the motherboard I can test the voltages with a multimeter?



Maybe at the voltage regulators..... with insulated tips!

And a very accurate DMM.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewIte...


Of course the one above is overkill!

A $10 DMM will give you a good idea but won't be very accurate.
May 31, 2006 1:39:50 PM

Hmmm... wouldn't know where to start....

But can anyone who knows for sure tell me if I should go with the settings in the BIOS or the readout in windows?? Please?
May 31, 2006 1:53:30 PM

Quote:
Hmmm... wouldn't know where to start....

But can anyone who knows for sure tell me if I should go with the settings in the BIOS or the readout in windows?? Please?




I think you can trust the BIOS over windows 90% of the time.
May 31, 2006 1:59:36 PM

The thing is, when your in the bios, your system is acting to where the system has some kind of load on the system. Basically like running a dos program, to where your CPU usage is higher.

When your system is running an OS (windows, linux) the OS has more control the amount of load going on a system.

I know my vcore fluctuates allot when the CPU is at idle. When the CPU is at 100 percent usage, then I see it become at a stable reading to where it isn't jumping around, and closer to what I set it at in the bios.
May 31, 2006 7:13:37 PM

Sorry its been awhile since I overclocked (haven't played a game needing it for awhile) and I can't remember the raw numbers, just the percentages.

If you change only the one voltage and the reading reflects that change then its the right sensor.

Most affordable test equipment has a 5-10% accuracy, unless you are also an electronics hobbist I would just give up after verifying you are using the right sensor.

Besides each CPU's is different, so even if you had a 100% accurate voltage reading it wouldn't give you any info on how much voltage your paricular CPU can safely handle or needs to reach x clock speeds.

Its all trial and error. You change the settings then test the results.

Prime 95 set to Priority 10 Large FFT's seems to be the best at letting me know that I pushed the system too far in the shortest about of time.
June 1, 2006 3:33:44 AM

I wouldn't even worry about it.

It's ok for windows to report less V.
!