Question RAM not stable at XMP (Z490 Aorus Master) ?

[Assaf Patishi]

Hi everyone,
I have 32GB (2x16) G.Skill Ripjaws V 4000mhz CL16 (16-16-16-36) and Z490 Aorus Master motherboard. This motherboard is not on G.skill's QVL (for this specific kit) but I bought this kit anyway
When running the default XMP voltage (1.4v) it is not stable, and after some testing I am able to run it stable at 1.43v (I set it manually). I will also note that when running at XMP profile, the VCCIO and VCCSA are at 1.34-1.35 (this is the motherboard automatic values).
I run this board on default settings, not manually overclocking or anything.
I am interested to know why the Z490 Master can't run this memory on the default 1.4V. What exactly prevents it from doing so? maybe some specific settings in the bios? or maybe the excessive VCCIO? I read once that too high VCCIO can also cause instabilities.

G.Skill QVL has other Z490 motherboards from MSI and Asus but not Gigabyte's so I suspect it is something related to Gigabyte's motherboards in general and not only the Master. I am really curious to know what it is that's causing this behaviour.
I will appreciate your input on this subject.

 

[Lutfij]

You might want to factor in that not all memory controllers will perform the same in spite of seemingly have the same processor on the same motherboard with the same ram kit. There are minor discrepancies in the manufacturing process so the advertised 1.4v for X.M.P could hold true for an older platform. You will also need to factor in that the QVL is a list of all ram kits tested in the lab/factory prior to the board's launch. If the board had a QVL for all ram kits on the market to date, then the motherboard wouldn't have seen the light of day(release date). Last thing to mention is that not all BIOS and voltage regulations are the same, some BIOS will show 1.4v but in reality 1.44v is being pumped into XYZ component.

What BIOS version are you on for your motherboard?

 

[Assaf Patishi]

You might want to factor in that not all memory controllers will perform the same in spite of seemingly have the same processor on the same motherboard with the same ram kit. There are minor discrepancies in the manufacturing process so the advertised 1.4v for X.M.P could hold true for an older platform. You will also need to factor in that the QVL is a list of all ram kits tested in the lab/factory prior to the board's launch. If the board had a QVL for all ram kits on the market to date, then the motherboard wouldn't have seen the light of day(release date). Last thing to mention is that not all BIOS and voltage regulations are the same, some BIOS will show 1.4v but in reality 1.44v is being pumped into XYZ component.

What BIOS version are you on for your motherboard?

Hi, thanks for your reply. I am on F3 version (first version), and I forgot to mention that I use 10900k CPU. I intentionally didn't update the bios because I had no reason to, it works just fine in this version.
I don't believe that bios update will solve this issue, Gigabyte didn't advertise RAM stability improvements in any of their updates descriptions.
I would really like to know why other motherboards can run this memory in 1.4V and in my motherboard I need 1.43V. I also don't think that the IMC is to be blamed cause the board's giving it enough juice (1.35v), I only needed to raise the DRAM voltage to make it stable, so I don't think it's the IMC in this case.
I also tried to mess with the "Memory enhancement" feature in the bios but it didn't change much (even on "Enhanced stability" mode), so I revert it back to "auto". I don't mind running this at 1.43 but I just curious as to what's id different in Z490 Master motherboard that it needs more DRAM voltage to run this kit. Maybe because it runs the CPU out of specs? but if that is the reason than isn't it more connected to the IMC? and like I said, the IMC is getting more than enough juice. it's only the DRAM voltage that I need to raise.

 

[DRagor]

I just curious as to what's id different in Z490 Master motherboard that it needs more DRAM voltage to run this kit.

You are seeing it wrong way. It may need different voltage to run the kit in different unit of same model. Just as different kit of same RAM model could need different voltage on your board. We only notice that when board actually fails to work with default voltage so you might be surprised but that's how it is.

 

[Assaf Patishi]

G.Skill tested this RAM kit on various Z490 motherboards and some were able to stay stable and went into the QVL. The Gigabyte Z490 Master is not one of them.
I am sure that if I would use this memory in one of the tested boards it would be stable in XMP. I also emailed G.Skill before I bought this kit and they say that this RAM is not compatible with my motherboard.
I also sure that if I would try this RAM in other Z490 Master units it would still not work properly. This is not a specific unit issue but something in the way this motherboard works is making it not compatible with the XMP 1.4V.
I want to know what it is. What is the difference between the Z490 master and the MSI Z490 Unify that the latter is on the QVL and the former isn't.
I mean..1.4V is 1.4V right?

 

[DRagor]

I mean..1.4V is 1.4V right?

Well, no It's like saying all boards have same quality VRMs which obviously is not true. The problem is motherboard get 3,5 and 12 V from PSU and has to convert them to whatever it needs (like 1.4 in your example). One board will convert to 1.4001 and will work with your RAM while the other may convert to 1.3999 and fail.

 

[Assaf Patishi]

Well, no It's like saying all boards have same quality VRMs which obviously is not true. The problem is motherboard get 3,5 and 12 V from PSU and has to convert them to whatever it needs (like 1.4 in your example). One board will convert to 1.4001 and will work with your RAM while the other may convert to 1.3999 and fail.

Yeah, but in my case even with 1.41 it's still not stable ( only 1.43 can keep it fully stable), so this can't be a little variation in voltage. And like I said, it's no accident that Gigabyte's boards are totally missing from the QVL for this specific kit. I believe that there is something in the way the Gigabyte motherboards work that make them not compatible with G.skill high speed RAM kits. I just want to know what it is

 

[DRagor]

I believe that there is something in the way the Gigabyte motherboards work that make them not compatible with G.skill high speed RAM kits. I just want to know what it is

That may be reasonable assumption, but I doubt anyone but Gigabyte engineers would know what it is.