Four sticks of DDR5 6600mhz ram will not boot with XMP

The original poster is trying to run 2 Dimms per channel on their AM5 motherboard. This is supported by AMD, just at substantially lower frequencies. AMD's official listed support is 3600MHz versus 5200MHz for 1 Dimm per channel.

Your response however is to claim that they're trying to run quad channel (which they're not) which isn't supported (this is true to be fair, neither the motherboard nor the CPU have the capability to run quad channel) and this is why their memory isn't running as expected. That's not really the case as there are other dual channel platforms (mostly Intel) which have no issues running 4 DIMMs across 2 channels like OP is trying to do.

The issue is just quite simply that the Ryzen memory controller is bad, as it has been since Ryzen 1000 launched, and as such it struggles hard with the strain put on it by running 4 memory modules. It's entirely possible AMD could fix these issues with future Ryzen processors by redesigning the memory controller which wouldn't require moving to a quad channel platform.

I hope that clarifies some of the misunderstandings, but if you do have more questions I'd encourage you to do some research into the difference between 2 dimms per channel and quad channel. It tripped me up a few times when I was starting out as well, and I do often catch myself saying "quad channel" when I mean "4 DIMMs".

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VikingFuneral-@reddit

I'm claiming they are; It's more that's usually the only reason to run 2 dimms

If someone doesn't know why they need more than 2 dimms they definitely don't need it

I'm just pointing out they are related, 2 dimms per channel can't run at higher frequency for the same reason quad channel can't; The CPU's memory controller wont be able to handle it

Because here's the kicker; None of us actually know if OP is running 2x dual channel, or quad channel or shit, even single channel at this point

We don't know what motherboard they have, or what dimms they have

The people replying to me are just replying with their own assumption and pretending my statements are invalid even though it's just as valid as what I'm being told.

So if what I'm saying is invalid; Then any other assumption from others is equally invalid

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KING_of_Trainers69@reddit

I'm claiming they are; It's more that's usually the only reason to run 2 dimms

Or higher capacity. Maximum size of a DDR5 DIMM is 48GB so to get above 96GB you need more than 2 DIMMs. OP mentioned that they're using 32GB sticks, so 4 of them makes 128GB.

None of us actually know if OP is running 2x dual channel, or quad channel or shit, even single channel at this point

Yeah we do. They're running 2 dimms per channel dual channel. They said they have a 7950X3D and 4 DIMMs. This CPU supports dual channel memory and nothing higher. You can check AMD's spec page.

https://www.amd.com/en/products/processors/desktops/ryzen/7000-series/amd-ryzen-9-7950x3d.html

All AM5 CPUs are wired for dual channel DDR5 only and correspondingly all AM5 boards are wired for dual channel DDR5. It is not physically possible for them to be running quad channel because the traces do not exist on the motherboard or the silicon on the CPU for that to happen.

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VikingFuneral-@reddit

It supports dual channel yes like all damn motherboards for well over a decade

But you are purposely being obtuse I'm not saying they are running quad channel, but if they are TRYING to, if won't work

And like quad channel if their memory controller on their CPU won't support 4 dimms at high speed then it won't support 4 dimms at high speed

That fact still hasn't changed.

The fact people have gotten so stupidly confused about this being an objective fact is baffling.

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KING_of_Trainers69@reddit

People are getting confused because you've introduced quad channel as a concept into a conversation which has nothing to do with quad channel.

No one mentioned quad channel before you did. You've assumed apropos of nothing that the OP is attempting to get it to work.

People are getting confused because what you're saying is incorrect but also that you're not good at communicating what your actual point is.

And like quad channel if their memory controller on their CPU won't support 4 dimms at high speed then it won't support 4 dimms at high speed

You've written the same sentence twice would you like to rephrase this?

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VikingFuneral-@reddit

If it won't support 4 dimms in quad channel it won't support 4 dimms at all, what's hard to comprehend that?

The ability to manage memory is because of the CPU's memory controller, and what the motherboard supports.

There's zero reason to have 4 dimms unless it's quad channel.

You don't need 128GB RAM on a damn consumer performance PC.

By default; Quad Channel is the default and original configuration for 4 dimms.

When you get sold 4 dimms of memory in a single kit they are often advertised as quad channel memory kits.

The memory channel setup hasn't been determined. Just because you plug 4 dimms in, doesn't mean the RAM is automatically running quad channel or 2x dual channel.

Cheaper motherboards which don't support either, and if a CPU doesn't support it, then the 4 dimms will end up just running at single channel performance.

Which is basically what quad channel and 2x dual channel is.

Single dual channel is always the best performance on a consumer PC for traditional applications

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KING_of_Trainers69@reddit

If it won't support 4 dimms in quad channel it won't support 4 dimms at all, what's hard to comprehend that?

Because it's not true? Dual Channel Intel CPUs work completely fine with 4 DIMMs

There's zero reason to have 4 dimms unless it's quad channel.

You don't need 128GB RAM on a damn consumer performance PC.

You have a very narrow view of what computers are used for. Not all PCs are for gaming, and the 7950X3D is squarely a prosumer CPU; there are plenty of prosumer workloads that can use all the RAM that gets thrown at them.

The memory channel setup hasn't been determined. Just because you plug 4 dimms in, doesn't mean the RAM is automatically running quad channel or 2x dual channel.

It does actually. It will automatically run in dual channel mode.

Cheaper motherboards which don't support either, and if a CPU doesn't support it, then the 4 dimms will end up just running at single channel performance.

Please can you find a single motherboard for a modern mainstream platform which doesn't support Dual Channel?

Which is basically what quad channel and 2x dual channel is.

No it isn't. Unless you mean that the drop in frequency is equivalent to dropping back to single channel which is a more reasonable argument, but it's not what you've said.

Single dual channel is always the best performance on a consumer PC for traditional applications

This was never under contention.

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VikingFuneral-@reddit

You really like to put words in my mouth don't you?

I said motherboards won't always support 2x dual channel, not that they won't support dual channel. They aren't the same.

And yes. The drop in frequency is literally the point I have made every step of the way..

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KING_of_Trainers69@reddit

If you're not capable of stating your argument intelligently then people are going to interpret it in a way you don't intend.

And yes. The drop in frequency is literally the point I have made every step of the way..

No. The point you've made the entire way is that the culprit is the lack of quad channel support. Quad channel was never relevant to the conversation and you've just muddied the waters by talking about it when it has no bearing.

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VikingFuneral-@reddit

And you also did the same by going off the only other assumption that it was running in 2x dual channel, when theoretically their motherboard could only support single dual channel and therefore also be running in single channel mode.

I literally own a Z170 motherboard that does that.

If I'm not helpful. None of you are helpful

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KING_of_Trainers69@reddit

I literally own a Z170 motherboard that does that.

Please link to the board and to where it says explicitly that this does not support 2 dimms per channel. I'm not considering any board which only has two DIMMs slots.

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VikingFuneral-@reddit

Feel free to link to a board that specially says it supports two dimms per channel

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KING_of_Trainers69@reddit

https://www.gigabyte.com/Motherboard/Z790-AORUS-ELITE-AX-rev-10/support#support-memsup

That was easy

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VikingFuneral-@reddit

Okay good for you. And when you see a motherboard that doesn't say it supports it you gonna insist it still does?

https://www.overclockers.co.uk/gigabyte-ga-z170x-gaming-3-intel-z170-socket-1151-ddr4-atx-motherboard-mb-528-gi.html

Only supports single dual channel memory mode

This board has zero statements regarding dual channel still being enabled with 4 dimms

Just that 4 dimms are supported OR dual channel is supported.

But I can bet any money you'll insist it supports both at the same time

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KING_of_Trainers69@reddit

https://download.gigabyte.com/FileList/Memory/mb_memory_ga-z170x-gaming3.pdf?v=d9551fd649de5b0dd6f5e62260d0ba7e

check the QVL dude.

• When enabling Dual Channel mode with two or four memory modules, it is recommended that using the same capacity, brand, speed, andchips of memory modules and also installed in the same color of DDR4 slots.

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VikingFuneral-@reddit

And? Doesn't mean anything

Because it literally says as I said (even on the board you linked) the speeds will be forced to a lower speeds, exactly like 4 dimms aren't properly supported and performance is substantially lower

That's just copy paste info they have on all their boards

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GhostsinGlass@reddit

You're so confidently wrong about this it's hilarious because you think 2DPC1R has anything to do with quad channel.

Do you know what 2DPC means?

Here is some baselines using AM5 and the 4x24GB kit I mentioned. Of the last 5 baselines, 4 are AM5

BL2304202 - Ryzen 9800X3D

BL2293939 - Ryzen 7950X3D

Bl2280882 - Ryzen 9950X

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VikingFuneral-@reddit

You literally said 2DPC1R = Quad channel

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GhostsinGlass@reddit

I did not you trolling asshole. I said !=,

!= means DOES NOT EQUAL.

2DPC with 4 DIMM slots, 2 DIMMs per channel.

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ImVeryUnimaginative@reddit

Try using two sticks.

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Mango-is-Mango@reddit

Or lowering speed

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Helpmehelpyoulong@reddit

They could lower the speed too

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VikingFuneral-@reddit

Quad channel memory needs to be supported by the CPU, yours does not.

Therefore you can't expect to run higher than the lowest speeds.

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SirIWasAlwaysHere@reddit

The CPU absolutely supports two backs of dual-channel DIMMs; it doesn't need quad channel to run 4 DIMMs.

The problem is that AM5 CPUs really dont want to run much above DDR5-5200 when they have 2 banks of dual-channel DIMMS (i.e. 4 DIMMS). The memory controller has a hard time maintaining stability in such a situation.

Which is why 1 bank of two identical DIMMs is the preferred configuration for AM5 - pretty much all will run at 6000 stablely, while it might be able to run at 6600, but no guarrantees even then.

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VikingFuneral-@reddit

Literally nothing you just said contradicts what I said.

Funny that; When your CPU doesn't support quad channel it can only run at default speeds

And when you run double banked dual channel you can only run at default speeds.

It's almost like those two things are directly related or something and are caused by the same problem 🤣 the CPU not supporting it

If a CPU doesn't support quad channel at full speeds, it won't support dual channel 2x at full speed either. Because as you pointed out is the fault of the memory controller ON THE CPU

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SirIWasAlwaysHere@reddit

Notice that "full speed" can't be run on those systems that support quad channel.

No CPU (by either AMD or Intel) will run DDR5-6600 in quad channel. They're all running it at 4800 or 5200. None support XMP or similar.

You're missing the point badly.

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GhostsinGlass@reddit

You are very confused.

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GhostsinGlass@reddit

If you were going to use 4 DIMM on AM5 there is only one kit on the market that can do CL30 6000+ out of the box for 2DPC1R,

It's the only 4 DIMM kit on the market as well and very expensive. $400 USD on perpetual backorder in US, $560 CAD here in Canadam

CORSAIR CMH96GX5M4B6000C30

Check your motherboards QVL, It is on there guaranteed. It is on nearly every x670 x870 etc AM5 board QVL.

It's SK Hynix 3GB M Die, 32GB if SK Hynix will be older 2GB A die, being 24GB DIMMs they are also single rank whereas yours are most likely dual and 2DPC2R is much harder to run compared to 2DPC1R.

There is a non-RGB, and a Titanium version, all that changes is the heatspreader. Just change CMH to CMK, CMP etc in the mosel number.

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dabocx@reddit

Is this four identical sticks?

You may need to bump them down to 6000mhz which is the ideal for Ryzen for most situations. Though with four sticks you may need to go down further.

DDR5 and higher speeds with 4 sticks is kind of a mess

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NewestAccount2023@reddit

Four identical sticks from two kits is different than four sticks in a single kit: the latter always has worse timings. If you try to use two stick timings for four sticks it's not going to work, four sticks is harder on the memory controller so the timings have to be looser.

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