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  #1  
Old 12-20-2017, 04:22 PM
Brendan McCoy Brendan McCoy is offline
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Default CMD32GX4M4E4000C19 XMP Instability

CPU: i7-8700k
Motherboard: ASUS ROG STRIX Z370-E GAMING (bios 0605)
Memory: CMD32GX4M4E4000C19

I am trying to get my memory to run stably at the specs on its product page

Speed: 4000MHz
Tested Latency: 19-23-23-45
Voltage: 1.35V

However, memtest86 and prime95 validations quickly show memory errors.

I was wondering if anyone could help me find out if I can dial in any settings to get stability. My core overclock to 5ghz has been validated, but I am doing all of my ram testing without my core overclock first to eliminate it as a source of instability.

I know my memory isn't on the motherboard's QVL, but it seems I never see dominator on vendor lists, and an identical Vengeance kit is on the list. I've heard the same ICs are on both products, just higher quality and better validated ones are in Dominator. I'm entirely open to the possibility that this isn't the case and Dominators just have a sexy tax.

I have tried using XMP and manually applying the paremeters, as well as upping VDIMM and VCCSA + VCCIO and no luck.

I've noticed that if I apply the parameters of the next fastest Dominator kit,

Speed: 3866MHz
Tested Latency: 18-22-22-40
Voltage: 1.35V

I do not throw any errors in a default memtest86 test (other than "RAM may be vulnerable to high frequency row hammer bit flips.", is this a cause for concern?).

A prime95 test on this seems stable, at least much more so than the XMP parameters.

Is it possible for me to achieve the specs on the box, or is this a case of "stability isn't guaranteed for these specs" for my motherboards speed support and the listed RAM specs?

Last edited by Brendan McCoy; 12-20-2017 at 04:30 PM.
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  #2  
Old 12-22-2017, 08:10 AM
c-attack c-attack is offline
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Asus lists maximum DRAM capability as 4 DIMMs@4000MHz for that board. You are right there. Working at the limit usually brings these kinds of difficulties and this is with the CPU in the normal state. 4000 DRAM and stock CPU clocks seems like a bad trade over 3866 and 5.0GHz. You are doing the right things and can keep at if you like, but I would take the 3866 and 5.0 and move on. Memory instability is really infuriating and time consuming. Let it ride for 6 months and give it another go with a more mature BIOS. I can't imagine any meaningful performance differences between 4000 and 3866, but that lock up that requires an OS re-install will ruin your week.
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  #3  
Old 12-29-2017, 02:38 AM
Cpt.Planet Cpt.Planet is offline
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Could be a limitation on the CPU IMC or maybe the IMC becomes unstable if the CPU temp is to high. You might want to try lowering VCCSA and VCCIO and see if it helps. Also you could also try an older bios Version 0428
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Old 01-04-2018, 03:05 PM
Deenoga Deenoga is offline
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Having the same problem myself, although I will freely admit, I do not know anything about overclocking, voltages, etc so I don't go near that stuff.

I have CMD32GX4M4E4000C19, ASUS Z370 Maximus X Hero and a BX80684I78700K.

I had 16GB of the exact same RAM for a couple of months and everything ran perfect at 4000MHz. I decided to buy myself an Xmas present of a new 32GB kit. Soon as I put it to 4000, game crashes and blue screens galore. I sent x2 kits back but they all had the same problem so it clearly wasn't the RAM itself.

Currently running at 3733MHz with no issues; in my head I've settled for that, but seems a waste buying the 4000.

Possibly could my CPU not handle 32GB at 4000? It all ran great with 16GB though.
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  #5  
Old 01-05-2018, 05:36 AM
dakotha dakotha is offline
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I have the same issue running this kit at 4000 but I am using Rampage VI Extreme and 7980XE. I have already RMAd one kit since one stick was not recognized at all. Well, kit is not on the QVL but it is on the Rampage VI Apex QVL. Any tips?

Btw, 3800C17 runs very well.
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  #6  
Old 01-05-2018, 09:03 AM
c-attack c-attack is offline
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Quote:
Originally Posted by Deenoga View Post
Having the same problem myself, although I will freely admit, I do not know anything about overclocking, voltages, etc so I don't go near that stuff.

I have CMD32GX4M4E4000C19, ASUS Z370 Maximus X Hero and a BX80684I78700K.

I had 16GB of the exact same RAM for a couple of months and everything ran perfect at 4000MHz. I decided to buy myself an Xmas present of a new 32GB kit. Soon as I put it to 4000, game crashes and blue screens galore. I sent x2 kits back but they all had the same problem so it clearly wasn't the RAM itself.

Currently running at 3733MHz with no issues; in my head I've settled for that, but seems a waste buying the 4000.

Possibly could my CPU not handle 32GB at 4000? It all ran great with 16GB though.
Generally, 2x8GB is going to be easier to run than 4x8 on a dual channel board. Unfortunately, at this time I think you are approaching the limit. Keep an eye on your System Agent (SA) and VCCIO voltages. The auto settings can be strong and more is not necessarily better for these values. My 8700K kit arrives today, but I haven't purchased new RAM yet because I am stuck on this same point. I would prefer a 2x16 kit, but there are very few above 3200 at this time. There are a lot more 4x8GB high speed kits, but the ceiling is going to be lower for a little while until the BIOS matures.

Presumably, you don't notice any real performance differences between 4000 and 37xx. Given the rather exorbitant cost of memory right now, you might consider waiting this one out unless you need the extra 16GB immediately. I think I had come to this same conclusion earlier in the week, but this helps solidify that idea. I am looking at that same kit in 2x8, so I am glad to hear you were able to run 4000 right from the start.

Last edited by c-attack; 01-05-2018 at 09:07 AM.
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  #7  
Old 01-06-2018, 12:33 PM
Deenoga Deenoga is offline
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Quote:
Originally Posted by c-attack View Post
Generally, 2x8GB is going to be easier to run than 4x8 on a dual channel board. Unfortunately, at this time I think you are approaching the limit. Keep an eye on your System Agent (SA) and VCCIO voltages. The auto settings can be strong and more is not necessarily better for these values. My 8700K kit arrives today, but I haven't purchased new RAM yet because I am stuck on this same point. I would prefer a 2x16 kit, but there are very few above 3200 at this time. There are a lot more 4x8GB high speed kits, but the ceiling is going to be lower for a little while until the BIOS matures.

Presumably, you don't notice any real performance differences between 4000 and 37xx. Given the rather exorbitant cost of memory right now, you might consider waiting this one out unless you need the extra 16GB immediately. I think I had come to this same conclusion earlier in the week, but this helps solidify that idea. I am looking at that same kit in 2x8, so I am glad to hear you were able to run 4000 right from the start.
I do wish I hadn't bothered with the 32GB kit. I knew there wasn't going to any noticeable difference as I only play games on my PC so it was overkill. I just got the idea in my head and I had the cash so thought why not, now I can't bring myself to downgrade back. I am my own worst nightmare.

But you mentioned about the bios; do you think, in the future, it may run at 4000?

Amazon do a 2x16 3466 MHz kit, just incase ytou hadn't seen it (amazon.co.uk).
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  #8  
Old 01-06-2018, 12:59 PM
c-attack c-attack is offline
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Will 4x8@4000 run in the future? Probably. How long that will take is another matter. When I first got X99, 4x8 above 2666 was a struggle. It really wasn't until the second year anything above that was plug and play. Those last one or two rungs at the published board limit for frequency can be challenging for a longer duration. It certainly won't be next month for easy drop in and done.

However, there is another way to look at this. You doubled your RAM capacity with only a drop from 4000 to 3733. That is not the worst trade, if you need or want the capacity. I cannot imagine any real world performance differences at those speeds, but you are also one of the few people who can swap the two kits back and forth and compare read/write/copy/latency. I use 10-11 of 16GB of RAM on X99 on a regular basis. I would also like to move up to 32GB and I am more likely to run into a capacity limitation before I run into a speed limitation.

Incidentally, I am curious what kind of read/writes you get with 4000. I am going to put the new board in shortly, but will start with my 4x4 kit @3200 until I figure out which of those two variables is the more pressing.
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  #9  
Old 01-06-2018, 01:31 PM
Deenoga Deenoga is offline
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Sadly, I've already sent the 16GB kit back. The 32GB kit worked fine at 4000 initially so I foolishly sent the other kit back. Then all hell broke loose. I do still have a second 32GB kit that I haven't sent back yet (learning my lesson). I can run whatever tests, if any, might be useful for you.
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  #10  
Old 01-06-2018, 01:39 PM
c-attack c-attack is offline
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Quote:
Originally Posted by Deenoga View Post
Sadly, I've already sent the 16GB kit back. The 32GB kit worked fine at 4000 initially so I foolishly sent the other kit back. Then all hell broke loose. I do still have a second 32GB kit that I haven't sent back yet (learning my lesson). I can run whatever tests, if any, might be useful for you.
No, don't go to any trouble. But I would also be curious about your read/writes at 3733. I am going to try and see how far my 3200 XMP kit will stretch, but I think 3733 will be out of reach.
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  #11  
Old 01-08-2018, 03:41 AM
dakotha dakotha is offline
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Bump my post earlier. ;)

I've had nothing but trouble with this kit. I tried my another kit with my 7980XE and could actually run a hour of RAM Test with my way lower bin 64 GB 8x8 3200 C16-18-18-36-2T Corsair Dominator Platinum kit at the same setting as this "4000" kit. Eventually I got errors to pop up too, but with this 4000 kit, I manage to get an error in under 2 minutes so it seems it is actually much worse. I also tried with a 7900X CPU and another R6E board and it's no better...

Currently trying 3600 16-16-16-36-2T, fingers crossed.

I have the Rampage VI Apex too, but only the 7740X I can play with. If the sticks don't work in dual channel mobo on that mobo, I will definitely RMA this kit again...the 7740X on the Apex should support even DDR4-4400 (or 4500 for that matter) kits.
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Old 01-09-2018, 11:44 AM
c-attack c-attack is offline
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Quote:
Originally Posted by dakotha View Post

I have the Rampage VI Apex too, but only the 7740X I can play with. If the sticks don't work in dual channel mobo on that mobo, I will definitely RMA this kit again...the 7740X on the Apex should support even DDR4-4400 (or 4500 for that matter) kits.
Don't confuse motherboard maker "supports" with guaranteed to work. When pressed, they concede it is all overclocking and there is no guarantee or warranty for failing to reach those marks. Unfortunately, memory training is a lot of work and it is most likely required as you approach 4000 MHz and above. You can keep swapping to different brands and sets hoping to find XMP sub-timings that are a perfect match for your settings, but the odds are not with you. It probably will require a lot of fiddling.
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  #13  
Old 01-11-2018, 02:43 AM
dakotha dakotha is offline
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Quote:
Originally Posted by c-attack View Post
Don't confuse motherboard maker "supports" with guaranteed to work. When pressed, they concede it is all overclocking and there is no guarantee or warranty for failing to reach those marks. Unfortunately, memory training is a lot of work and it is most likely required as you approach 4000 MHz and above. You can keep swapping to different brands and sets hoping to find XMP sub-timings that are a perfect match for your settings, but the odds are not with you. It probably will require a lot of fiddling.
Yeah, I hear you. It seems at least half of the sticks are good on the R6 Apex with 7740X on XMP, only needs some fine tuning for the VCCIO and VCCSA. The other two sticks didn't even boot , have to try those again.
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