DFI Venus - Vdimm raises

[merlin76]

Hello,

when I power on my computer after a longer period being turned off Vdimm in BIOS shows 2.69V, 2.71V are set.

When the PWM temperature raises the Vdimm continuously raises up to a maximum of 2.76V (BIOS). That is a 0.07V difference if BIOS readings are correct. Smartguardian reports higher voltages, too. It goes from 2.68V to 2.72V. When the PWM temp lowers the Vdimm lowers, too.

I believe it is dependend to PWM temp but it could be another component on the mainboard, too. I will test tonight by putting a fan in front of the mofsets. PWM temp is between 30°C and 45°C. It's only Vdimm which raises, Vcore and other voltages are rockstable. With my previous RDX200 I did not encounter Vdimm instabilities.

I've read that people running on phase have problems with higher Vdimm when the board gets cold.

What could cause such an issue, a faulty resistor, power supply...?

[MAZ]

I believe that it is a characteristic of the Vdimm regulator,Winbond W83321.

[Lastviking]

0.2 more vdimm for me when i used -12c air on the board.

[Zebbo]

merlin, can you check that with DMM ?

[merlin76]

Thanks for your input. :)

My intention that Vdimm raising has to do with PWM temp was wrong. But when placing a big fan into direction of the voltage regulator Vdimm lowered from 2.76V to 2.72V (BIOS).

@ MAZ

I've never seen such a thing before. If it was an ECS board I would have thought it's a cheap crap. But such a component on a board like Expert/Venus? :eek:

@ Zeboo

Sorry, I don't have a DMM. I could buy one but I'm in fear to short it. :(

Are there any other guys with Vdimm instabilities (Expert and Venus)?

[Lastviking]

Thanks for your input. :)

My intention that Vdimm raising has to do with PWM temp was wrong. But when placing a big fan into direction of the voltage regulator Vdimm lowered from 2.76V to 2.72V (BIOS).

@ MAZ

I've never seen such a thing before. If it was an ECS board I would have thought it's a cheap crap. But such a component on a board like Expert/Venus? :eek:

@ Zeboo

Sorry, I don't have a DMM. I could buy one but I'm in fear to short it. :(

Are there any other guys with Vdimm instabilities (Expert and Venus)?

I dont think its a stabilty issue, the vdimm have good stability but it change some when its hoter or colder in the room.

[MikalCarbine]

My expert seems to undervolt on the Vdimm horribly, I am not using it now though because of that

[merlin76]

I bought a DMM and checked real Vdimm. BIOS and DMM values were mostly the same, sometimes differed by about +-0.01V.

[MikalCarbine]

I did the same with my Expert last night, vDimm was always .01v higher than what BIOS read to me, which was always much lower than what I set for the vDimm in the BIOS, and tends to vary