Kingston KSM26ES8/8ME (8GB DDR4-2666 CL19 ECC) does 3600 stable on Ryzen at 1.35V

Good afternoon everyone!

I recently bought this memory (Kingston KSM26ES8/8ME, 8GB single-rank DDR4-2666 CL19 unbuffered ECC) for a little CAD/CAM/CNC workstation and wondered how high it would clock. Long story short, it does 3600 with 22-22-22-22-47 timings at 1.35V on Ryzen and I was able to run PassMark MemTest86 V8.1 for two days without errors (no ECC corrected errors either). It also posts 3733 but that gives some ECC corrected errors after a few minutes of running the test. I’m not sure if that’s just my board limiting the maximum clock frequency - increasing the voltage didn’t help at all, so it might be (tried up to 1.45V with no change at all).

CPU: AMD Ryzen 7 2700X
Board: Asus Prime X470-PRO
RAM: Kingston KSM26ES8/8ME (2x)
RAM voltage: 1.35V
RAM clock: 3600
RAM timings: 22-22-22-22-47, everything else on auto

The chips are Micron E-Die according to the datasheet of the DIMM. I got two sticks of the same type, which were however manufactured in different factories - one is from Taiwan, one from China. Both of them clock equally high, so it’s unlikely that I just got lucky and got that one really good stick. Of course, a sample size of 2 still doesn’t say that much.

The sticks also don’t like tight timings, even with additional voltage.

Obligatory proof “screenshot”:

If all (or most) of these sticks clock similarly high, they’d be absolutely perfect for Ryzen workstations. Maybe that’s something for Wendell to find out?

Jonathan (aka ttlhacker)


can you post subtimings and command rate for posterity? default training/subs vary wildly from mobo to mobo

@tkoham Of course!

Also, if you’d like me to try some specific settings, let me know.


The procODT setting might get you a little more stability at tighter timings. On my hynix ecc I was able to go from CL15 to CL 13 at 2733 (they are not great overclockers). With other timings tighter also. I was also able to get 2800 stable for the first time with changes to procODT, but the timings had to be so loose that 2733 was better. Like I said though, these aticks are not great over clockers.

On your micron chips you might be able to get tighter timings or more freq.

ProcODT didn’t make any difference, unfortunately. It crashed at 40 ohms or below, as well as at 80 or above but I wasn’t able to raise the frequency or lower the timings at any setting in-between those two.

Oh, that is too bad. Well, I mean too bad it didn’t make the ram overclock any better. Seems pretty good for what it is even if ProcODT didn’t help!

Still the fastest ECC you can get for a Ryzen?
Thanks :slight_smile:

@ttlhacker any idea what attribute of the RAM makes it achieve this overclock? I got a similar motherboard, but I’m wondering if I can achieve it with this memory instead:

Same CAS latency & frequency…

The biggest factors are the ram chips and the PCB of the dimm.
He had Micron rev. E chips, which are known for clocking high, being cheap to make and for putting less load on the memory controller. Their downside is that they dont really do tight timings.

The memory you linked is Registered ECC (ECC RDIMM), that does not work at all with Ryzen, only EPYC supports RDIMMs. Ryzen only supports ECC UDIMMs (unbuffered memory).

Thanks - didn’t catch that!
@Methylzero I’m going to try a 32GB KSM26ES8 - and just hope that it overclocks like the 8GB version.

Considering buying this instead. Any idea how the Kingston will compare to the Samsung?

I’d like to reach at least 3200mhz with stability.

Late response, but as owner of 4 of those I can safely say it sucks. Its Samsung m-die that runs on 3200 with timings 18-19-19-41 and sub timings such as tRC on 66 and RFC on 560. It can be overclocked to 3600, but with timing of excess of 25 its not worth it. Beside 3400 is the sweet spot of this memory. I am running 20-19-19-41 with relative tightened sub timings such as tRC on 70, tWR on 24, tCWL on 19 and lastly RFC on 560. I have to say this memory doesn’t want to be overclocked and its rather underwhelming compared to its 16 gb cousin. Avoid is my recommendation. Extra note: If tRP or tRAS is any lower than 19 or 41 it won’t even boot. CAS latency 16 on 2666 refuses to boot. Google buildzoid video on the ram. I based my overclock on his.

Thanks @FutureFade
Too late, bought them, I searched and didn’t find that stuff - I figured Samsung was highly recommended. You had to increase the voltage too, right? Not just the timings?

Everyone uses these terms ‘x-die’ in threads, and I can never see how it corresponds to the spec sheets. How does one determine what ‘die’ their memory is?

Considering there are only 4 slots, I wanted to get a 32gb module. Are there zero good 32gb ECC modules, really?

This one? Where he says, “I’m straight up impressed”?

I used taiphoon burner utility required by the DRAM calculator. It shows what the nanoseconds are for each of the timings + what die it is:

Yes I also had to increase voltage, 1.35V, and I added a fan, because one of the module is close to VRAM. Causing it to reach high 60 Celsius . In general you don’t need put a fan on your dram. The one that aren’t on the VRAM side is just chilling at around 50~.

While that video is 11 months old by now I was more talking about this one:

Because this is one applicable to our platform.

Edit 1: Scrolled through the video, he managed to get it to 3600(!) with command rate T2 on CL 17(!!). That’s impressive, however it is on coffee lake system and my memory controller or the ram stick doesn’t like anything lower than 25 for cas latency at 3600. Maybe if I set T2 command rate.
A link for T1 vs T2 command rate:

Edit 2: Apparently setting 1.35V didn’t actually apply. I was running stable 3400 mhz on 1.2V, sort of. I did get an bios settings error prior to booting into linux. I set the voltage 1.25V to mitigate this error. Setting 1.3V causes it to spit out errors for some reason.

Checked again lately and these are the fastest ECC RAM I can find in this category… Not sure which is better:
Kingston KSM32ED8/32ME
Samsung: M393A4K40DB3-CWE
Supermicro DR432L-SL02-ER32

The last 2 models you listed (Samsung and Supermicro) are registered memory modules and will only work on server platforms (such as Epyc).

Should have bought more of those back when I did… The same exact modules are now like 25% more expensive where I am 0_0

go with MTA18ADF2G72AZ-3G2E1 (16GB 2R8 3200 CL22)

most of them can do 3600 CL16

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I’m guessing you tested it? Do they have a 32gb per module version? I wonder if it can be mixed with a Samsung M391A4G43MB1