4xDDR5 DIMMS with 9950x3D and EXPO fail to boot

[Mike81]

I just put together a 9950x3d on a gigabyte x870 gaming wifi6 motherboard and I wanted 128Gb of ram, so I went for corsair vengeance 6000Mhz cl30 4x32Gb(CMH64GX5M2B6000Z30 - advertised compatible with both XMP and EXPO).

The system booted and I was able to install Windows.

Upon changing the ram settings in BIOS to enable EXPO1 to benefit from 6000Mhz memory, the system does not even boot, I get a red led for ram, waited a couple of minutes and it restarted on its own asking to reset the BIOS config to default values.

Since then I ran a bunch of tests and as soon as I try to use all 4 slots with EXPO 1 enabled the system does no longer boot. I have tested 4x32 as well as 2x32 and 2x16(CMH32GX5M2B6000Z30K) with the same speed and clocks. Intensively tested all the dimms separately and all tests were successful at full speed, the problem arises only when using all four slots of the MB.

Is this a limitation on the CPU side or the motherboard or both?
Is there any chance of getting a 9950x3d to work with 128Gb of ram at higher than default settings?

I am willing to change the MB and/or the RAM, but I do not know what to go for?!

[WereCat]

4x 6000MT/s is quite difficult to run without some major manual tweaking.

Usually you will max out at around 5600MT/s with 4 sticks.

 

It's recommended to have just 2 sticks unless you need the extra RAM at which point you will be sacrificing speed. Can't have both right now on Ryzen.

[Hinjima]

Just now, Mike81 said:

I just put together a 9950x3d on a gigabyte x870 gaming wifi6 motherboard and I wanted 128Gb of ram, so I went for corsair vengeance 6000Mhz cl30 4x32Gb(CMH64GX5M2B6000Z30 - advertised compatible with both XMP and EXPO).

The system booted and I was able to install Windows.

Upon changing the ram settings in BIOS to enable EXPO1 to benefit from 6000Mhz memory, the system does not even boot, I get a red led for ram, waited a couple of minutes and it restarted on its own asking to reset the BIOS config to default values.

Since then I ran a bunch of tests and as soon as I try to use all 4 slots with EXPO 1 enabled the system does no longer boot. I have tested 4x32 as well as 2x32 and 2x16(CMH32GX5M2B6000Z30K) with the same speed and clocks. Intensively tested all the dimms separately and all tests were successful at full speed, the problem arises only when using all four slots of the MB.

Is this a limitation on the CPU side or the motherboard or both?
Is there any chance of getting a 9950x3d to work with 128Gb of ram at higher than default settings?

I am willing to change the MB and/or the RAM, but I do not know what to go for?!

This is a limitation of the memory controller.  Getting 4 sticks for RAM to work at 6000Mhz on Ryzen 7000 and 9000 is very difficult.

This is why we have started to see higher capacity kits of 2 like 2x24GB or 2x48 GB.

I suggest going with a 2x48GB kit instead of 4x32... Yes, you will be losing a little bit of RAM but you will get EXPO to work.

[Millios]

2 minutes ago, Mike81 said:

Is this a limitation on the CPU side or the motherboard or both?

Yeah is the short answer

AM5 does not do high speed 4 sticks you either a) settle for slower speeds or b) go for less capacity/same capacity in 2 sticks rather than 4

You have a snowballs chance in hell of doing high speed 4 sticks on am5 regardless of your CPU

 

[freeagent]

Some guys can do it, I have a hard time getting anything more than 4800MT/s stable.

 

I bought 4 sticks because the internet said it was hard to run and I didn't believe them.

[Phosfiend]

I'm doing a new build (similar to the OP), and would love a lot of RAM (rendering, mograph, gamedev). 96gb (2X48) seems like it should just work (and quickly).

That said, I like the idea of 192GB, but I'm not interested in headaches. If I'm not that worried about a bit of speed loss, is it doable or a fools errand? 96GB of stable RAM is infinitely more valuable than 192GB of sketchy RAM.

Thanks!

[cmndr]

You'll likely be stuck with 2x48GB RAM unless you want to pay the premium for 2x64GB. 

 

If you need a bigger working set and are OK with a dirty hack... Intel Optane as page file is surprisingly good. 
https://www.reddit.com/r/photogrammetry/comments/gdifmf/optane_is_great_as_virtual_ram/

 

 

[freeagent]

You can run high capacity no problem, but high capacity fast is something else. I am tempted to ditch this X670E and move to X870E to see if there is better compatibility.

[igormp]

If all you need is 128GB, you can opt into 2x64GB sticks, since those are now a thing, which should enable you to run at 6000MHz.

[Phosfiend]

Thanks folks, unfortunately 2x64GB isn't a great option in my region (Canada) regardless of price.

There are two 128GB crucial kits that are reasonably priced, but seem either too new or too rare to buy...

I have almost all other components of my build sitting here. I'll wait a couple more days and keep my fingers crossed for a 2x64 kit to become available.

But I suspect I'll likely go for a moderate speed 2x48GB kit & if I feel the need for more memory I might buy a second kit and run it at lower/default speeds...
 

There seem to be two pretty vocal camps on this one, and it's hard to parse because my use case is probably not like most folks. ie: never run 4 sticks it's the worst! & 4 sticks is fine as long as run them slow!

Ideal scenario for me is maximum stable RAM, higher speeds is really just a bonus for me. This system will be a big upgrade regardless, so even if I run the memory at default speeds it's going to be a big change.

 

decisions, decisions...

 

thanks!

[igormp]

4 minutes ago, Phosfiend said:

There are two 128GB crucial kits that are reasonably priced, but seem either too new or too rare to buy...

It is indeed new, it only became available at retail mid February.

4 minutes ago, Phosfiend said:

Ideal scenario for me is maximum stable RAM, higher speeds is really just a bonus for me. This system will be a big upgrade regardless, so even if I run the memory at default speeds it's going to be a big change.

I'm currently running 4x64GB at 4800MHz stable with my 9950x, can recommend.

[Phosfiend]

12 minutes ago, igormp said:

It is indeed new, it only became available at retail mid February.

I'm currently running 4x64GB at 4800MHz stable with my 9950x, can recommend.

Ah, nice to hear - building around a 9950x as well. That makes the 4x48GB approach sound pretty doable then.

 

thanks!

[SheepleFlawker]

On 4/27/2025 at 6:26 AM, Mike81 said:

I just put together a 9950x3d on a gigabyte x870 gaming wifi6 motherboard and I wanted 128Gb of ram, so I went for corsair vengeance 6000Mhz cl30 4x32Gb(CMH64GX5M2B6000Z30 - advertised compatible with both XMP and EXPO).

The system booted and I was able to install Windows.

Upon changing the ram settings in BIOS to enable EXPO1 to benefit from 6000Mhz memory, the system does not even boot, I get a red led for ram, waited a couple of minutes and it restarted on its own asking to reset the BIOS config to default values.

Since then I ran a bunch of tests and as soon as I try to use all 4 slots with EXPO 1 enabled the system does no longer boot. I have tested 4x32 as well as 2x32 and 2x16(CMH32GX5M2B6000Z30K) with the same speed and clocks. Intensively tested all the dimms separately and all tests were successful at full speed, the problem arises only when using all four slots of the MB.

Is this a limitation on the CPU side or the motherboard or both?
Is there any chance of getting a 9950x3d to work with 128Gb of ram at higher than default settings?

I am willing to change the MB and/or the RAM, but I do not know what to go for?!

i have the 7945hx and oc 96gb 5600 crucial to 6000 and stable, resetting your bios to default is probably your problem, when you buy a pc like this and you want to make it perform you have to do some research, takes 5-10 mins for my ram to boot after adjusting sometimes

... hit up discord minisfourm has a sub reddit for your board