Won't boot if memory speed >2666 mhz

pmrowczynsk10000276

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Apr 12, 2022
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Have two separate motherboards, both on the x570 chipset. The most recent is a Ryzen 5 5600x, while the other is Intel. Both have the same 'upper memory speed' issue.

* AMD : MSI MAG X570 TOMAHAWK WIFI AM4 AMD X570 SATA 6Gb/s ATX AMD Motherboard
* Two matching sets of memory: DDR4-3200 2x8GB and DDR4-3000 2x8GB

When putting in the memory pairs into only slots 2 & 4, I can get into the OS when the DDR4-3000 and FCLK is set to 1500

But when I fill up all four slots, it won't POST unless I downgrade to DDR4-2666 with FCLK set at 1333 (1/2) after clearing the CMOS

Since I can't even get the delete button (hold down to enter BIOS to work, and it won't go 'two failures, enter bios' on this MB) I've been stuck clearing the CMOS via jumper which is annoying to say the least. The Intel MB will work normally (hold delete, fail twice and enter bios). XMP is not enabled when doing playing with the speed changes.

Is there an issue with mis-matched (but compatible at lower speeds) memory in all four banks where DDR4-2666 / 1333 mhz is the maximum?

On my Intel MB I see other options as well, such as DDR4-XXXX 22@100x1.0 or DDR4-YYYY 23@100x1.3 whereas the memory profile is only showing DDR4-2666 on the AMD MB by comparison. And I couldn't get any of the x1.0 to work there either.

Follow up steps include

* Upgrade the firmware (Apr-2020)
* Try increasing the FCLK to 1500 mhz or some other magick in the BIOS
* Live with it. You only lose a potential 10% gain

But ideas as what the issue is? And also why the BIOS "hold delete on power on" isn't working when there's a failure?
 

citay

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Mixing different kits of RAM will confuse the CPU's memory controller and can lead to all kinds of problems. If you want 32 GB, the best is to use 2x 16 GB.

Read my thread RAM explained: Why two modules are better than four / single- vs. dual-rank / stability testing, which should hopefully clear up a bunch of things, including if you really need 32 GB.

Have two separate motherboards, both on the x570 chipset.
This doesn't quite match with you later saying that the other board is an Intel-based one. Also, you don't have more than two XMP profiles. So whatever RAM frequencies you saw on Intel, they were not from the XMP. Usually you enable XMP (profile 1) and then, after pressing F10 to save and reboot, you have the maximum RAM speed the modules were rated for from the manufacturer.

I have not heard of this supposed "hold delete" trick. If the settings fail, it should offer to enter the BIOS all by itself. MSI boards (at least the Intel-based ones) are usually pretty good at recovering from memory settings that don't pass memory training. It will either show the "F1/F2 overclock failed" text message after a while of unsuccessful memory training, or sometimes it may get stuck and you hold the power button for a few seconds for a hard shutdown. Then on the next boot it should recover to the F1/F2 screen and you press F1 to enter the BIOS and try some other settings.

So yeah, the main thing is not to mix different RAM. It's like putting different sized wheels on your car.
Sometimes it might work kind of alright, but other times everything will fall apart when you try to go fast.
 

Richj44

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And also why the BIOS "hold delete on power on" isn't working when there's a failure?
I can't add anything to your main issue, but on my 590 board "hold delete on power on" has to be set in BIOS to work. Same goes for the the "fail twice, enter BIOS" feature.
 

pmrowczynsk10000276

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Ah, was able to reboot into the other system, it's on the Z370 Chipset

MPEG Z390 GAMING EDGE AC MS-7B17
Intel Core i7-9700K @ 3.6GhZ
Patriot DDR-4400 C19 Series 2x8GB
G.Skill F4-3600 C16 2x16GB

Again, both will not go past 2666mhz and the memory itself is more than capable of a faster clock speed.

The AMD x570 MB will not detect a memory problem and simply fail to POST. When I try to boot into the BIOS settings for a MB, and there isn't a problem, I hold down the DEL key and have for years to get in (e.g. Z390 MB). There is no failure-detection on the x570 and it just cycles though the settings to "try twice" are set in the BIOS. There is no response when hitting F1/F2 and there is no white-on-black telling me things are reset, or not working. Yeah, held down the power button (beats climbing under the table, resetting the CMOS by a screw driver, powering on, and seeing if there is a display change / option to enter BIOS). When there is no problem, the "hold delete" works just fine to enter the BIOS settings page.

Anyhow ... One would think that the lowest common denominator (3000MhZ) would work. And in fact, when I run each pair of memory - they boot and operate just fine. It's just that when I daisy-chain them, it's when things don't work for the MB.

Read the post on the memory controller and not sure why there would be confusion. I've set a lowest common denominator (in terms of clock speeds) and as stated above, works fine with a single pair. So there must be:

* bad bank (doubtful ... it works at a slower clock speed)
* other setting

Since we're advised to fill bank 1 first, we can't (or maybe shouldn't) fill the second bank (odd row). Don't think that's it - so that means there's some other setting at play here under some "auto" settings.

Something like CAS timing? For example in the above with C16 and C19 memory, if it default to C16 memory then it wouldn't work for the C19, so we'd have to default it to the lowest common denominator (like the speed) of C19. When we set AUTO for memory speeds, it'll default to DDR4 2133MhZ (not sure about the FCLK speed) and presuming it'll do the same for some CAS timings. BUT when you crank up the MHZ specifically ... it then fails making me think that it's more specifically related to the speed setting and not a CAS or other setting.

The problem then is that when I swap the pair of memory (older one in one pair, fail to boot, swap the two pairs around, fail to boot) that would presumably pick up the first pair settings (e.g. CAS) and use it for the other where it's supportable (presumably).

The Intel is my workhorse (programming rig and former flight sim) whereas the AMD is the gaming rig. Been putzing around this stuff (and doing IT support in a former life) since the 8087 was an add-on chip. Most of the time, it's a set-and-forget, and rarely get the opportunity to delve into the deeper aspects except when something goes wrong.

Hence, I'm fine w/ 2666MhZ but want to figure out what the combination needed to get the MB to correctly POST at 3000 MhZ when the memory actually does support it :/
 

citay

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First off i would do a BIOS update to the newest version. Then try again.

About the RAM slots, you have to populate them in a specific order. The slots right next to each other are not for the same kit of RAM. Instead, you first populate slots A2 and B2, and if you want to add two more sticks, you put them in A1 and B1. So, always A2 and B2 first for one kit of RAM (those are the second and fourth slots from the left).

So let's look at what we have now:

Two matching sets of memory: DDR4-3200 2x8GB and DDR4-3000 2x8GB
Patriot DDR-4400 C19 Series 2x8GB
G.Skill F4-3600 C16 2x16GB
You have four completely non-matching kits of RAM, with even vastly different properties in the Intel system. One kit of single-rank 8GB modules with a very high-spec XMP, and the other kit consists of dual-rank 16 GB modules with good-spec XMP. This is bound to cause problems, the poor memory controller doesn't know what to do. There is no good middle ground between those kits, they need quite different parameters to address them properly. But there can only be one set of parameters that can be active for the entire memory system. So this is a big conundrum. You'd be much better off just running the 2x16 GB kit here. Your IMC would thank you massively. This should work at XMP no problem at all.

Again, remember the analogy with the car tyres. You are trying to mix racing tyres with street tyres, but the street tyres will fall apart quickly on the race track. The handling will be all over the place too.

Whenever you see DDR4-2133, -2400 or -2666, that's the safe JEDEC profile. The BIOS will default to that on first boot, and whenever your enabling XMP will not pass memory testing. The AMD-based boards are worse at recovering from failed memory training. Maybe with the newest BIOS they will have improved memory compatibility somewhat.
 
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