Adjusting voltages on motherbaords that allow this feature

[blakerwry]

I hvae a question... err rather would like to hear a debate on the topic...

If you are viewing the voltage monitoring software for your mobo and notice that your CPU or RAM voltage is a little low... should you raise the values in order to get the monitoring software to show the correct values?

ex:
CPU voltage is sensed to be 1.74 (instead of 1.75). Do you:
A) set the voltage to 1.76 to achieve 1.75
B) run @ 1.74
C) something else...

I guess there are several things to consider. (1) The monitoring sensors may be off... or within their margin of error... (2) The voltage reaching the CPU, RAM, etc might be different from what is getting to the sensors (3)The motherboard might be designed to run with voltages slightly below spec (4) everything else....

 

[CougTek]

Re: Adjusting voltages on motherbaords that allow this featu

ex:
CPU voltage is sensed to be 1.74 (instead of 1.75). Do you:
A) set the voltage to 1.76 to achieve 1.75
B) run @ 1.74
C) something else...

C) something else...like trying a higher quality PSU. Low voltage are often caused by a lacking PSU or a poor power circuitry on the motherboard.

 

[blakerwry]

As long as the PSU is supplying voltage with the 5% and 10% allowances and my machine is stable, I wouldn't replace it.

I have seen examples such as what I gave several times.. .yes mainly with "no name" PSU's...

My Antec smart power 350 on a Soyo Dragon plus is 0.6% low on the 3.3v line and as much as 0.8% low on the 5v line, but almost 1.5% high on the 12v side of things. This equates to a CPU voltage that is 0.5% high and a memory voltage that is 0.8% low.

That seems pretty high quality compared to my "no name" 400 watt PSU... I don't have the specs available, but I know that the 12v line is real high... maybe ~6% and the 5v line is pretty low, but within 5%. On this computer I know the CPU voltage is .5% low.

Most of these values are pretty small, and I would assume be within the margin of error for the sensors... just for reference, I believe the 3.3v and 5v lines from the PSU can be +/- 5% and everything else can be +/- 10% and still be in spec.

 

[Clocker]

If the machine is stable, I would not change anything. If it were not stable, I'd up the voltage a bit.

I think a few % is well within tolerance when you consider the compounded variability of the PS output, the motherboard sensors, and the slight variation of resistance found in electronic components.

C

 

[blakerwry]

Do you think that the sensors are likely to be off? I think that there must be a lot of variation on temperature sensors.

I've seen on forums where someone switched motherboards and their temps went up or down... This might be due to changing the thermal paste and different airflow casued by moving cables and such however.

But if you look at temps for people running a particular mobo they seem to have a corrilation. AFAIK nobody has done any testing on a large scale, but I think it would be interesting.

 

[brwmogazos]

My Abit IT7MAX2 is undervolting both the ram and cpu...

It is the best P4 clocking board though and compared to the asus P4t533R for example that does NOT undervolt(slightly overvolts) the Abit reaches higher cpu speeds even with undervolting.So its a matter of the boards design i'd say.My 2.53ghz P4 has reached 3106mhz @ 1.66V actual voltage.I will have to vid pin it as high as 1.75V(dont want electromigration to occur) in order to reach the cpus (safely running)limits.
So when running at stock i DONT up the CPUs core volt and Rams Voltage if the system is stable.After all less voltage means lower temps

 

[blakerwry]

that's pretty much how I see it.

 

[NRG = mc²]

1.74v isn't anything to be worried about... all components have a tolerance, including the sensors, as brwmogazos said, some mobos (eg my Asus) overvolt (if you set it to CPU default it gives 1.8v instead of 1.75, I was running it like this for months untill I could be bothered to change to jumpers to manual override and set it to 1.75), others undervolt (MSI 845 Ultra), nothing much to worry about as long as its within reason and the system works fine.

 

[NRG = mc²]

BTW.. some mobos also over report temperatures, my A7V266E gives around 10C higher CPU temperature readings than other boards supposedly to compensate for innacuracies.

 

[blakerwry]

With temp sensors now being located on the CPU die I hope that the reported CPU temps will start to become consistant across different models and brands of motherboards.

 

[brwmogazos]

With temp sensors now being located on the CPU die I hope that the reported CPU temps will start to become consistant across different models and brands of motherboards.

Well not really...for example the ASUS p4t533R and my IT7MAX2 had a 10C temp difference.My IT7MAX2 monitors slightly higher temps than it should be whereas the ASUS a lot lower in this case...

BUT...Anything more than 1.75V in 0.13micon chips may kill the chip due to electromigration.I am going to volt mod the cpu as high as 1.75V but nothing more than that...even though my chip comes with a 3 year warranty(bought it retail) i dont wanna kill it by running 24/7 full load as even at 1.75v electromigration effects have been noticed...

 

[blakerwry]

Well, i guess it is really just a thermister or other type of sensor that is located on the CPU... there is still monitoring hardware that is necessary to read the temperature... This system will always have some error and discrepencies from board to board.


What is all the new talk about electromigration.. this has been something that I was aware of over 5 years ago when overclocking processors. I guess it has just become common place for many people to be overclocking their processors and some where along the lines we have let in the dunces who think that if the motherboard supports a certain voltage they should be able to use it no matter what... no consequences....

In my opinion - and I thought this was pretty much a standard - if you want to be able to use/sell your CPU in 2 years don't over volt at all.... if you want to throw your CPU away in a couple years.. by all means go ahead and overvolt upto about 10%. If you overvolt any more than 10% you better have the $$ to buy a new processor on hand at all times.