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Motherboards => Overclocking, Undervolting => Topic started by: Dotcom on 28-August-19, 10:08:40

Title: DRAM Voltage always higher by 200mV than what was set
Post by: Dotcom on 28-August-19, 10:08:40
This is with a B450 Gaming Pro AC on 7B85v18, Ryzen 3600, and 2x8GB Crucial Rev.E

So which one is the actual voltage? The one I set it to or the one that it reports? Doesn't matter what value I set, after I reboot it always has +200mV reported on the side.

As it stands, this is impossible to overclock consistently... Very frustrating.
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: Chike on 28-August-19, 11:40:42
As it stands, this is impossible to overclock consistently... Very frustrating.
Make sure MSI is aware of it >>How to contact MSI<< (https://forum-en.msi.com/index.php?topic=107326.0)
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: akildaud on 09-September-19, 02:44:28
I'm having the same issue. Did they get back to you on this?
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: Dotcom on 09-September-19, 09:03:10
Yes, the reply was:

"Regarding your concern, about the ram voltage, we are really sorry, the voltage value has a little deviation, this is normal"

This is definitely not normal, but whatever. Just treat it as 200mV higher than what you write there, no other voltages are treated the same from what I can see but I avoid changing VDDP, VDDG etc.
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: Chike on 09-September-19, 09:48:53
Would this happen with bios default loaded, or even with just xmp selected, no other changes?
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: buddyw53 on 11-September-19, 12:52:38
I've never known voltages REPORTED in the BIOS screens to be representative of actual operation in the OS. Instead, always boot into the OS and use a reliable utility to report voltages.  HWInfo64 is generally considered 'best' for Ryzen since it's frequently updated and reports processor SMU telemetry stream, the SVI2 readings.  I'd say that if voltage is reporting 200mV high in the OS, and under loaded conditions, then adjust accordingly.  

The reasons voltage readings from within BIOS is inaccurate can be several, including the processor being in REAL mode, not 386 enhanced mode.  Which would mean it's only running on one core, one thread of execution and not accessing more than 1MB of memory.

And lastly, it's unfortunate but many of MSI's B450 offerings really aren't the best IMO. Even though they may provide good power for higher core count processors I've found the VRM on my B450 Mortar to be 'loose' and can't be made to hold tight voltage tolerances through load variations.  That's something I've had to live with for overclocking by tolerating a bit more voltage at idle than I like to have it remain at stable levels under heavy load.
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: Dotcom on 12-September-19, 10:11:22
Thank you for the feedback. Unfortunately that is not the case, while running CPU-Z i've  checked both MSI Command Center and HWinfo64 and there it is at 1.352V under load when I set the voltage to 1.33V in the BIOS.

I was led to this board because I needed AC Wifi on a "budget", and VRMs were reported as on par with X470 boards - plan on getting an 8-core or 12-core in the future for this same system.

Meanwhile I got the RAM to where I wanted it, cheap RAM below 70ns latency and 1800 clock (2x effective), at only 1.35V... or is it 1.33? :rolleyes:
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: buddyw53 on 13-September-19, 16:08:10
....
Meanwhile I got the RAM to where I wanted it, cheap RAM below 70ns latency and 1800 clock (2x effective), at only 1.35V... or is it 1.33? :rolleyes:
Does it really matter?

The tolerance for DDR4 is really wide (up to 1.5V by JEDEC specification) so if you're worried about system stability you've a lot of room to just bump it up a notch or two.
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: Chike on 13-September-19, 17:23:28
There is no way to know which is the culprit the vrm or sensor without measuring it with reliable equipment.
But if you see 1.35 and no faults, why worry?
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: buddyw53 on 13-September-19, 18:33:53
There is no way to know which is the culprit the vrm or sensor without measuring it with reliable equipment....
Which itself is a challenge as even reliable equipment really should be calibrated at a certified metrology lab to know it's reading accurately.

In the end, we are all at the mercy of wide tolerance bands.
Title: Re: DRAM Voltage always higher by 200mV than what was set
Post by: Dotcom on 13-September-19, 20:06:13
More of a PSA I guess, some people might be thinking they're going for safe 24/7 voltages (1.45V i would say on these Micron Rev.E), but actually going higher. I did find it best to keep them under low voltage so I'm happy with it.

Appreciate all the feedback!