Vcore voltage drop under load normal?

[Placid]

I am not sure if I just never noticed this before but when my pc is idle my vcore voltage shows 1.91 close to the 1.90 I have it set at in the bios.
When I run a program with a good cpu load like prime 95 the vcore voltage drops to 1.87 and stays there until I stop the program then it returns to 1.91.
Is this normal?
I am using a 350w enermax power supply.
I guess I could be overloading it but not sure what to make of this.

[bdf24]

Mine does the same. At idle it's 1.87 and at full load goes down to 1.84 and stays untill I turn the prog. down as well.

I guess it makes sense. The chip is just hogging more power under load.

[Placid]

Thanks for the response.
What size psu are you using?
Are you running the pelitier off the same psu as the rest of your system?

[Phil]

I often notice a rise in temperature of my cpu followed by a 0.01-0.02v drop in voltage, I would guess that it is not really to do with the psu and more to do with the heat from the cpu causing greater resistance which in turn lowers the voltage slightly (this may be wrong as I know that if the current stays the same and resistance is increase the the voltage should go higher, but if the current drops slightly as well the the voltage would also drop due to the resistance)

[Endeavor]

this might be normal but im not sure because mine does the same thing

[SP]

It has to do with the quality of the voltage regulators modules on your motherboard and whether they can supply sufficent current as the current draw of the CPU increases. The resistance of the traces carrying the voltage to the CPU comes into play also. When the processor is under more of a load and more circuits inside the processor are active it will obviously draw more current. When the processor is halted or inactive fewer circuits inside will be active and it will draw much less current. Anyway, the voltage flucuations your seeing are the result of this. The voltage regulators may not be quite up to the task of delivering the current drawn or may be slow to respond to quick changes in current draw. Also as the current draw of the cpu increases the voltage drop across the resistance of the traces on the motherboard will increase. So, it has to do with the quality of the design of the motherboard. On some cheaper boards this is more pronounced and may account for reduced stability. On good boards like Tyan or supermicro you probably won't see this or if you do it will be much smaller.

[Placid]

Thanks alot.

[bdf24]

Placid (May 28, 2001 05:04 p.m.):
Thanks for the response.
What size psu are you using?
Are you running the pelitier off the same psu as the rest of your system?

I'm running a 431w Enermax. And yes the tec is running on the same psu. As is four 80mm fans, one 90mm fan, and one 120mm fan.

[DocClock aka MadClocker]

Yea, it's normal.
My question is why do you have an ata100 card when your board has native support for ata100?
Or it is a raid card, and you fergot to mention that?

I have the SH6, and I am running ata100 without an add on controler, but will soon get two more drives, and a raid card.

[Placid]

I use a card because I find the promise card faster (benchmarks)and I cannot get norton speed disk to work with the intel ata drivers in windows me.

[DaveB]

It has to do with the quality of the voltage regulators modules on your motherboard ................. So, it has to do with the quality of the design of the motherboard. On some cheaper boards this is more pronounced and may account for reduced stability. On good boards like Tyan or supermicro you probably won't see this or if you do it will be much smaller.

Yeah, SP is right on the money. I'm running O/C'ed PIII 700s on my Soyo SY-6BA+IV BX mobo, and another two PIII 700s on my Rioworks PDVIA dual VIA 133A mobo. All are O/C'ed over 933 MHz. The Soyo core remains rock steady at 1.95V whether under severe load or at idle. The dual mobo on the other hand, can vary by as much at 0.05V plus or minus.

[Rainmaker]

I had a soyo 6ba+iii that was rock solid but died after a voltage surge. It did not have the same voltage fluctuations as I do with my epox bx6 now. Much more stable too.