MSI x870 Tomahawk EXPO not working

D

derekfoster1971262029b

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Hi all, I recently bought the x870 Tomahawk with Ryzen 9950x and a 64 GB Ram Kit (2x 32gb sticks): Corsair cmk64gx5m2b6000z30. I am on the latest A16 beta bios and whenever I enable the EXPO setting the board fails to boot with A6 motherboard code - the RAM is rated at CL30 6000MHz. I have tried many different settings (EXPO on/off while manually setting 6000Mhz and lower speeds etc.) but nothing works. Also had MCR and Power down off and on but the system will only boot with the RAM at its default 4800 MHz CL40 speeds.
Any suggestions on how to get the RAM working at advertised speeds on this board would be greatly appreciated.
Thanks!
 
Solution
M
expo actually means overclocking

expo ram is "certified" to run at expo profile settings
cpu is "cerfified" to run at amd spec DDR5-5600
mainboards should be able to run the memory as stated in the QVL documentation (if the memory kit is not present in the QVL prepare for surprises)

so if you have problems with expo memory the percentages must be split like this

40% unlucky IMC (or other cpu related problem, mounting pressure for example)
30% unlucky ram kit (sometimes the memory needs a small tweak to run at expo values)
30% unlucky mb (defective memory lanes, very common on ddr5 motherboards, with no vendor exceptions)

this is why support have to answer like that
"in theory" the cpu is more likely to be the problem because...
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derekfoster1971262029b said:
Hi all, I recently bought the x870 Tomahawk with Ryzen 9950x and a 64 GB Ram Kit (2x 32gb sticks): Corsair cmk64gx5m2b6000z30. I am on the latest A16 beta bios and whenever I enable the EXPO setting the board fails to boot with A6 motherboard code - the RAM is rated at CL30 6000MHz. I have tried many different settings (EXPO on/off while manually setting 6000Mhz and lower speeds etc.) but nothing works. Also had MCR and Power down off and on but the system will only boot with the RAM at its default 4800 MHz CL40 speeds.
Any suggestions on how to get the RAM working at advertised speeds on this board would be greatly appreciated.
Thanks!
Click to expand...
Can you try manually setting the RAM in Bios to 5600 and report the results
If it runs at 5600 I would suspect you have a bad CPU
 
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I tweaked the settings to run at 5600Mhz and seems to be ok so far. Why would you mention a bad CPU? In all the PC's I have built I have never had a 'bad' CPU, its always been a RAM or motherboard issue for either a configuration issue or hardware failure.
 
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I also didn't check the RAM kit was on the MSI compatibility list when I bought it, there does not seem to be any 64GB kits on the compatibility list (48GB the largest). Being an early adopter of x870 and a 9xxx CPU is something I will just need to put up with for now but at least I can use the 64GB for now and in worst case drop it from 5600Mhz to 4800Mhz if needed for stability in the tools I use. Hopefully a BIOS update will come out at some point that helps with the EXPO issues and such but I can see there are still ongoing problem for B650 and X670 RAM configurations (particularly EXPO) when reading through various forums. I am coming from a very stable AM4 5900x system where everything just 'worked' out the box.

There is also a note in red on the X870 Tomahawk page under the compatibility tab that states the below:

1.CPU memory controller quality will affect the memory operating frequency. System reliability and stability could be impact by the status of higher temperature from DDR5 memory modules.
2.The partial DDR5 memory module will remain running at 4800MT/s because of the architecture design by the Ryzen 9000 series CPU.
 
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Yes, you're dealing with a new platform so certain things are not mature enough.
On the BIOS side you're going to see some improvements soon.

In any case, don't forget that anything over 5600 is overclocking for your CPU IMC:
https://www.amd.com/en/products/processors/desktops/ryzen/9000-series/amd-ryzen-9-9950x.html
Max Memory Speed
2x1R DDR5-5600
2x2R DDR5-5600
4x1R DDR5-3600
4x2R DDR5-3600

Also, as general rule: more memory you have, lower speed you can achieve.
For 64GB, DDR5-6000 is not a given, but a bonus!
So certain CPU samples cannot run that stable.
That's why @Alan J T told you he would suspect you have a bad CPU. :biggrin:
 
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Thanks @Alan J T and @RemusM - I'm not with the latest lingo on forums anymore so took the literal meaning of 'bad CPU' as it being possibly broken :) My tinkering days are over sadly to time but still enjoy building PCs and run everything at stock these days apart from usually trying to get RAM to run at its EXPO/XMP speeds but not always a given. At this stage I will be happy with running at 5600mhz knowing the CPU IMC limitations but when I get time I will try with tighter timings. Looking forward to any improvements a new BIOS will bring!
 
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In the interests of sharing, the attached is the only settings I changed in BIOS to run at 5600mhz with the 9950x, along with manually changing the primary timings to 40-40-40-77. That was it, after far too long trying to get it to run at the EXPO timings of 6000Mhz 30-36-36-76 through various settings.
 

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Cinebench multi-core score using the 5600mhz settings above. Will put it through one of my own workloads which are CPU/RAM heavy (astrophotography integration using Pixinsight). If it gets through a few hours CPU time with that it should be stable enough.
 

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derekfoster1971262029b said:
That was it, after far too long trying to get it to run at the EXPO timings of 6000Mhz 30-36-36-76 through various settings.
Click to expand...
Yep Problem is the CPU Internal Memory controller while it is in speck it is only just in speck get on to AMD and see if they will do an RMA
 
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I bought this board to use with a 9800X3D. Updated bios before cpu install to 7E51v1A16(Beta version) released on 10/30/24. I have the exact same memory kit but in 2x16 format. I too cannot run anything above 4800. Single stick can run at rated EXPO of 6000 30-36-36-76 all day, but as soon as a second stick is installed, I get the Ab post code. I'm chalking it up to BIOS and holding out for some new revisions to improve compatibility.
 
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jfrench068154502db said:
I bought this board to use with a 9800X3D. Updated bios before cpu install to 7E51v1A16(Beta version) released on 10/30/24. I have the exact same memory kit but in 2x16 format. I too cannot run anything above 4800. Single stick can run at rated EXPO of 6000 30-36-36-76 all day, but as soon as a second stick is installed, I get the Ab post code. I'm chalking it up to BIOS and holding out for some new revisions to improve compatibility.
Click to expand...
I have the same RAM and cpu, was able to run it (2x16) at EXPO 6000 for a few days but not without issues, weird crashes, the wifi disappears, nvme disappears (comes back with poweroff or clear cmos)... Today the EXPO profile simply disappeared from the BIOS and the memory is detected as 2x2Gb (yes, I only have 4Gb of ram now😭)... I wonder if I should return the MB and never look at MSI again...
 
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derekfoster1971262029b said:
Hi all, I recently bought the x870 Tomahawk with Ryzen 9950x and a 64 GB Ram Kit (2x 32gb sticks): Corsair cmk64gx5m2b6000z30. I am on the latest A16 beta bios and whenever I enable the EXPO setting the board fails to boot with A6 motherboard code - the RAM is rated at CL30 6000MHz. I have tried many different settings (EXPO on/off while manually setting 6000Mhz and lower speeds etc.) but nothing works. Also had MCR and Power down off and on but the system will only boot with the RAM at its default 4800 MHz CL40 speeds.
Any suggestions on how to get the RAM working at advertised speeds on this board would be greatly appreciated.
Thanks!
Click to expand...
I have the same problem with the same setup except a 9800x3d instead of the 9950x. I have an x870 tomahawk + corsair 2x32gb CMK64GX5M2B6000Z30 + 7E51v1A16 bios. The system boots with a cleared CMOS. All RAM preset settings (EXPO, AXMP, "Try It" on the slowest presets, Hynix preset) result in an Ab troubleshooting code. Same problem with all stick configurations (1 stick, 2 sticks, slots 2/4, 1/3, swapping sticks). Thanks to all who have shared their similar problems. This is a real, specific problem. Ignore the people trying to claim that this outcome is expected.
 
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IMO it really should work at 6000MT/s with 2 sticks. It's ridiculous that it doesn't. They sell the board as 8000+, specifically saying memory speeds are improved, then you can't get 6000? At the very least it's misleading marketing.
 
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Leon255156302e1 said:
IMO it really should work at 6000MT/s with 2 sticks. It's ridiculous that it doesn't. They sell the board as 8000+, specifically saying memory speeds are improved, then you can't get 6000? At the very least it's misleading marketing.
Click to expand...
Good point. The advertised claims (8400MT 1R, 6400MT 2R) specify Ryzen 9000 as well. Your issue feels even worse because it's manifesting as hardware failures. Your troubleshooting path must've been a wild ride. Not sure the best course from here but at least we know who to avoid in the future.
 
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Just to join the party I put my x870 Tomahawk + 9800x3d + CMK64GX5M2B6000Z30 rig together today updated to the latest BIOS and I see the same results as everyone else Ab after switching on EXPO. I've tried some other random troubleshooting advice I've found on forums like turning on "Memory Context Restore" and "Power Down Enable" but it hasn't helped.
 
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Also joining the party. Computer won't boot at all with expo enabled or if I set RAM clock over 4800MHz. CMK32GX5M2B6000Z30. I tried my friend's RAM stick, it was Corsair vengeance 6000MHz CL36 and it worked fine with EXPO enabled. I already ordered new sticks from Kingston. Seems like corsair sucks with this mobo.
 
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