# vcore voltage problem?



## M.T.Pilot

Hi folks,

My current computer (Intel Core 2 CPU 6600 @ 2.4 GHz with 2 GB of RAM, M/B: ASUS P5NSLI, ACPI bios revision 1104) has not been running well for weeks now (sudden black screens, CPU and PSU fans keep on running, automatic restart after a couple of minutes), and just now I might have gotten a bit of useful info on the cause. 

However, I'm not sure what the info signifies and what action should be taken. This is a warning that I got after my computer shut itself down (with CPU and PSU fans still running) and after it tried to boot itself (after a couple of minutes of black screen and fans running, as said), before the bios:



> ***Warning: H/W monitor status abnormal***
> 
> Please enter SETUP to check voltage, fanspeed or temperature status



When checking, I found that the Q-Fan Controller was disabled (I think it was like that already), but the odd thing was that the Vcore Voltage was presented in red numbers as: 1.02V

That can't be good.


The rest of the Voltage (3.3V Voltage, 5V Voltage and 12V Voltage) seemed alright, although the 12V Voltage was a bit low: 11.96V. The temperatures didn't look very strange either: CPU temp: 40 degrees C and M/B temp: 46 degrees C. Fanspeed: CPU fan speed was 2800 RPM, but both Power and CHA fan speed was 0 RPM. (Again, the 2 fans in the PSU itself are running, as is the CPU fan).

Anyway, the Vcore seems to be undervolted (it probably fluctuates, because the last couple of days, my computer has been running sometimes for hours on end, without shutting down).

I did not change any settings in the BIOS, concerning  voltage, fanspeed or whatever [so, no overclocking]). Those are the default settings:



> DRAM Voltage [auto]
> chipset core voltage [+1.4V]
> CPU termintation voltage [1.25V]
> VCore voltage [AUTO]



(CPU termination voltage means that below the set 1.25V the computer will shut itself off, I reckon?)

Additional info in the bios: "set a very high voltage may damage the coponent permanently! Set a very low voltage may cause the system to become unstable!"

So it makes sense assuming that VCore voltage problem, although not set or changed by myself, is the cause of the instability of my computer.

Two questions:

1) why does the CPU not receive the proper voltage?

2) will a new PSU solve this problem, or should other measures be taken?

Thanks!


M.T.Pilot


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## M.T.Pilot

(b.t.w. should the PSU be the problem, then I assume this thread should actually have been posted in the PSU-section of this forum... sry about that)


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## ScOuT

1.02v is very low for a Q6600. That could cause stability issues. Make sure your 4 or 8 pin CPU power cable is not loose, take it off and put it back on. You can manually set your voltage in the BIOS. I would set it at about 1.32. The lowest stock core voltage for any Q6600 stepping is 1.3125v.  I have seen people take a Q6600 above 1.45 volts overclocking it.

11.96 is right at what the 12v rail should be producing. My Antec 650w was 11.97 at full load doing an OCCT PSU burn It runs the PSU wide open with everything it has.


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## M.T.Pilot

Thanks ScOuT!

It's a 4-pin, I'll reconnect it (although I've recently done so, when I took out all hardware and put it in another casing in an unsuccessful attempt to solve the strange problem that I'm having with my computer).

So, you don't think the PSU is faulty?


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## ScOuT

I don't think it is your PSU. What exact PSU do you have anyway? One way to check is download OCCT and do a PSU burn for an hour or so. It will monitor all voltages and put your PSU at full load. 

You can also test part by part (CPU, RAM, GPU, PSU)

http://www.ocbase.com/perestroika_en/index.php?Download


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## M.T.Pilot

My computer (2007) was fitted with a cheap PSU (some $21): 

*A-Power Pure Black 680 Watt SATA ATX*

It has got a 3 settings switch to control  fanspeed. For a long time now, there are periods when this PSU is "acting up" in such a way that it seems that one of the (2) fans is going into overdrive, making a lot of noise that is not normal. 

I have to fiddle with that switch for a while, putting it in a lower setting, and then usually, after a while I can put it back up to the highest fan speed (I'm in the tropics) without any problems.

I have this problem on and off. Sometimes it will not take place for months, then it'll occur for weeks/months on end.

It might not be related at all to the undervoltage of the VCore, but on the other hand, it might...


I'll check out your suggested link and test, thanks!

(b.t.w. if it is not the PSU, what could it be? Mobo? CPU itself?)


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## JHM

I don't know if this is in any way related to your problem BUT :

My machine when first built, would 1) boot into black screens, (even during the windows install); 2) frequently have programs announce that they had encountered a problem and must close; 3) Give me the occasional BSOD; 4) abruptly shutdown and restart.

I took it to one computer shop and the guy said your processor is defective, (He was wrong), that he had tested it and with one or two cores running it was ok, but that as soon as the third and fouth core cut in it was failing tests.

I then took it to another computer shop where the guy got it running perfectly, but refused to tell me how he did it saying it was a secret; for which he charged me $90.00, (I found out later how he did it and that he was a crook).

With it working I took it home and began checking the bios to see what he had done. I found a couple of changes, but they turned out not to be related to the problem. Still messing around in the bios trying different settings to see what might cause this, I encountered a situation where the machine refused to boot until I cleared the bios thereby loosing the crook's changes, and all the problems came back.

I next checked all the voltage settings and found as you have that the processor voltage seemed absurdly low. So I jacked it up, BUT that still didn't solve the problem.

Then I went to a computer forum where I learned how to access Giggle Bite's SECRET, (Not mentioned AT ALL in the bios), RAM timing settings. Turned out the RAM was slightly defective, and would not support its stated timings. 

Mr. CROOK had slowed down the SECRET Giggle Bite RAM timings on defective RAM enough to get it to work, rather than reporting it as defective and assisting in getting it RMAed, in hopes that in messing in the bios, I would lose his settings by clearing the bios and have to go back and pay another $90.00

I found by running Memtest Deluxe that with the RAM timing and voltage settings at their "De Faults" I was getting 57 memory errors in one pass of Memtest. By changing the RAM timings from "De Fault" settings of : 5, 5, 5, 18, 3, 3, to 6, 5, 5, 18, 3, 3, it was able to run Memtest Deluxe for over 19 hours error free; and all the problems went away.  I wound up RMAing the RAM.

Hope this helps.


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## M.T.Pilot

Hi JHM, thanks for your info!

Apart from the BsODs, it seems pretty similar to what I am experiencing. I'm going to d/l the memtest and do some testing.

B.t.w. How did you know what settings to use for your RAM timings?

I suppose you can only RMA while your computer(item) is still under warranty, right?


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## M.T.Pilot

I ran the (free version) Memtest until some 110% without any errors. I plan to do an overnight test for more realistic results. However, as soon as the computer acts up again, (which it has not done throughout this whole day) I will loose the test data.


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## JHM

Re RAM timings, what I did at first was slow things down to 6, 6, 6, 21, 5, 5. All the problems stopped happening. Then I asked at another computer forum what I should try. Got nothing but wrong answers, - "Use DE FAULTS", so I wound up setting it back at Its FAULTS and incrementing it slower by 1 clock, planning to continue doing that till it worked. Got lucky and it worked on the first try, changed from 5, 5, 5, 18, 3, 3, to 6, 5, 5, 18, 3, 3.

Re RMAing Defective RAM, most RAM carries a lifetime waranty. It is supposed to last forever, so if defective you can RMA it.

Re all my problems with this machine, and what I tried, and what voltages I found, see the following link to the other forum I mentioned, where I only got wrong advice. 

http://www.clunk.org.uk/forums/gene...ce/25856-sc-x-my-nightmare-supercomputer.html

NOTE : You have to read the posts carefully, cause many different things were tried before I finally found the RAM was defective.


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## M.T.Pilot

thanks again JHM.

I'm thinking in my case it might not be the RAM after all... I ran the (free version) Memtest for about 12 hours: some 700% without any errors.

I'm going to go over the link you gave.

Cheers!


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