Question Mixed Ranked Ram

[The TrippyHippie]

Hello Peace and Love fellow tech lovers,

Just a quick question, my system had 32GB of Ram consisting of a matched set of 2 sticks of XMP DDR4 3200 that are dual ranked, which is really great man, as time has passed and AI becomming a thing, that sort of got me intrested in playing around with some models, while optimizing the models with ONNX I noticed my system ram was using around 30+ GB of system ram so I decided I wanted to add another 32GB but really wanted to max out the motherboard to 128GB as one model needed 80-95GB of system ram 😱

But due to budget and cost of living decided I will just have to make do with 64GB system Ram (4x16GB)
the second 32GB kit i got is the same brand as the 32GB kit i already had installed in the system, apart from one itzy bitzy thing, this 32GB kit is single ranked 🙁 Heavy man!

so I have put the matched dual ranked kit in channel one an the single ranked matched kit in the second channel, I also went into the bios and disabled memory interleaving due to using dual and single ranked ram sticks.

I am currently running them a the jedec ratings of 2133mhz, my CPU is the AMD R9 5900X which can offically support 4 sticks of single rank at 2933MHz or 4 sticks of dual rank ram at 2666MHz.

with the way I have the ram configured, channel 1 dual ranked ram sticks and channel 2 the single ranked sticks am i still able to run the ram at the offically supported 2 rank ram speeds of 2666MHz with the mix of ranked ram?

I know people will say you should of bought a four stick matched set in the first place and I would agree but not everyone can afford to buy the amount of ram they may (or may not need) at the time of building the system.

Personally I think its about time these big RAM companys started clearly putting on the front of the RAM packaging the RANK of the DIMMS you are buying just out of fairness even more so for those who cant afford to buy 4x sticks of ram all at once, or dont they really care about what you get just as long as they get your money and you take what your given 🙁 thats soggy lentils man.

 

[Darkbreeze]

so I have put the matched dual ranked kit in channel one an the single ranked matched kit in the second channel

This is likely your problem. You do not put both of one kit in one channel and both of one kit in the other channel. It is a DUAL channel configuration, and for that work you need one stick in channel A and one stick in the matching channel B. So, one kit should go in the 1st and 3rd slots and one kit should go in the 2nd and 4th slots. Or, in other words, put the DIMMs from one kit in A2 and B2 and the DIMMs from the other kit in A1 and B1.

Do not put both DIMMs from the same kit in A1 and A2 or B1 and B2. Otherwise it's the same as using entirely different kits/mixed memory. But even so, in MANY cases, if you are not using ONLY memory that ALL came from the same kit, it may still not play nice, even if it's the same model. And you've hit on what I try to explain to people all the time which is that memory manufacturers often tend to change the composition of a kit while retaining it's model number. That can result in problems.

Here is my usual spiel on mixed memory. You can read the entire guide, or skip to the section titled "Mixed memory (Or the odd man out)".

How To - Troubleshooting problems with PC memory (RAM) and XMP profile configurations

In the beginning, there was......BIOS Before you go ANY further, go to the manufacturer product page for your specific motherboard model AND revision. Revision is an important aspect because for any given motherboard there may be more than one version of that model which will be identified...

forums.tomshardware.com

I know people will say you should of bought a four stick matched set in the first place and I would agree but not everyone can afford to buy the amount of ram they may (or may not need) at the time of building the system.

This, is irrelevant. Some people also can't afford to build a NASCAR level racing machine, in which case, they don't race. The fact that somebody cannot afford to buy a kit that comes with all the memory they need does not, in any way, have anything to do with the fact that if they don't, they might not be able to do what they are trying to do without actually doing a lot of trial and error with various kits, which generally ends up being more expensive than the cost to simply purchase a kit with the capacity they need from the start. Or, you can opt to sell the kit you currently have, return the kit that won't play nice, and put all that money towards a single matched kit.

The first thing you want to do though is make sure you have the MOST currently up to date stable motherboard BIOS version installed. A lot of the time, simply updating the BIOS is all that is needed for a lot of memory issues to be resolved.

 

[The TrippyHippie]

Ah thank you so much, I'm a bit confused, I thought the first 2 slots were channel 1 and the second 2 slots were channel 2 for eaxample :

ram slots on motheboard I thought were in this order (when looking directly down at the motherboard)

slot1. (channel 1) Single ranked Kit
slot2. (channel 1) Single ranked Kit (dual channel) if using 2 sticks of ram
slot3. (channel 2) Dual ranked kit
slot4. (channel 2) Dual ranked kit (dual channel) if using 2 sticks of ram

so your saying the correct layout is like below and I should have the ram kits configured in that order, because from what i read It's best to keep the single ranked ram in one of the channels and the dual ranked ram in the other channel.

slot1. (channel 2) single ranked Kit
slot2. (channel 1) dual ranked Kit
slot3. (channel 2) single ranked kit
slot4. (channel 1) dual ranked Kit

also should the RAM beable to run the ram at 2666Mhz in that configuration with no issues? ( apart from not being the optimal config for ram (those RAM commpanys are slacking and lazy for not being up front and clearly displaying on the box what the Rank is for the Kit/s you are buying bit of a scam really) ) the kits are rated at XMP 3200)

The system will boot to windows with all 4 ram sticks installed (in any order) with XMP 3200 mode at 1.35v

Thing is, if using dual ranked ram, with four sticks of dual ranked ram the memory controller is supposed to be running at 2666Mhz or if using single ranked ram in all four slots the ram memory controller can support 2933MHz

so if i enable XMP but manually set RAM speed of 2666Mhz that should be ok and work as intened

I just wanted to try and keep everything with in offical AMD Spec (not into overclocking and will be happy with default spec of 2666MHz performance)

Edit: It's taken me quite some time to save for parts to build this system and I am not in a postion to buy a 4 stick matched set 🙁

It's taken me a very long time to save and upgrade, in the time its taken me to save up and slowly upgrade my PC time had already moved on to the next gen CPU and DDR5 but I am more than happy with my system and it performance It's the best PC I have ever owned and will meet all my needs.

so I was in the postion of already having 32gig wanted 128gig but would take to long for me to save up 270, also the 128gig was not a matched kit of 4 sticks they are 2 x 64gig kits, they dont offer 128 gig 4x4 kit with the ram i was looking at and seemed a fair price considering they are a quality brand name.

I had 80 (which took quite some time to save) and just excepted I can only realisticaly afford to get another 32gig kit

so Im just trying to make do with what I got given for my money.

 

[The TrippyHippie]

Just checked and I do have my ram in the correct slots

slot 1_A and 2_A would be channel 1 and slots 1_B and 2_B, would be channel 2 , Slot and channel configuration printed on the motherboard.

so surly putting the dual ranked kit in slots 1 and 2 mean they are paired in the same channel and the single ranked ram are paired the second channel slots 3 and 4 which is the recommend config,

In other words dont have a dual ranked stick of ram in the same channel with a single ranked stick of ram, or am i tripping out (Im doing my own head now) lol

my question still is with that lop sided config rank config will the memory controller still be able to run the ram at 2666MHz without having any hidden stablity issues?

I have tried to mitigate the lop sided channel ranking by disabling memory interleaving to put less stress on the memory controller.
otherwise the memory controller would be dual channel with dual rank setup in one channel (2x1R sticks of ram) and quad ranked ram in the other channel (2x2R sticks of ram)

The difference between interleaving enabled and disabled I'm not bothered about but stability I am, less stress on the memory controller hopefully the more stable when less chance of error/s when doing heavy work loads in the ram.

well thats my theroy anyway lol.

 

[Darkbreeze]

No, you don't. You are still confused. All consumer 4 DIMM slot motherboards that utilize a dual channel architecture, ALL of them, since there has been high density DDR3 memory, DDR4 memory and now DDR5 memory, have EXACTLY the same population rules. You just do not understand what you are seeing when you look at the user manual.

ALL, ALL consumer motherboards made in the last, at least ten years, and actually more like the last fifteen, use THIS population configuration. There are NO consumer motherboard models that do not, which have four DIMM slots and use dual channel architectures with double data rate DIMMs. None.

And this, is why.

https://forums.tomshardware.com/thr...-2nd-and-4th-slot-first.3195865/post-19720591

So, you can do whatever you like, but if you do not put one kit, assuming the use of two distinctly different memory kits like you have, in slots A2 and B2 and one kit in slots A1 and B1, you are not populating correctly and you are never going to have any success with your configuration. So, that's up to you. I've only been doing this for like 35 years, so.......

 

[Darkbreeze]

It would of course be helpful to know your full hardware specifications ESPECIALLY your motherboard model, so I can pull the population rule directly out of your motherboard's user manual and show you where you are going wrong. It's the same place that everybody goes wrong, thinking that you want both sticks in the two slots that are the same channel, but that is not how the architecture is designed to be populated. If you want the memory to operate in DUAL CHANNEL, which is how it was designed to be populated, then you MUST have either four matched DIMMs, in which case it doesn't matter where you put them, or you must have one DIMM in the A2 and one in the B2 that are matched and then if using four DIMMs you want the second set in the A1 and B1 slots. If using only two DIMMs you NEVER want to use the A1 and B1 slots, which are the first and third DIMM slots, with the A2 and B2 slots ALWAYS being the second and fourth slots. That goes for every high density four DIMM slot DDR3, DDR4 and DDR5 consumer motherboard made by ASUS, ASRock, Gigabyte, MSI, NZXT, and so on.

 

[The TrippyHippie]

well after testing it appears that I had my system ram configure100% correctly I indeed need to keep the single ranked ram kit in slots A_1 and A_2 which is channel 1 and the Dual Ranked Ram Kit in Slots B_1 and B_2 which is channel 2.

I think you must have mis-understood me as your config advise for setting up mixed paired ram is incorrect but thanks anyway it's all sorted and running great at ddr 2667Mhz 1.35v with interleaving enabled

The correct confiuration when using matched a pair of single ranked Ram sticks and matched a pair of dual ranked Ram sticks is as follows (for people who maybe running in to issues)

slot1. A_1 (channel 1) Single ranked Kit
slot2. A_2 (channel 1) Single ranked Kit
slot3. B_1 (channel 2) Dual ranked Kit
slot4. B_2 (channel 2) Dual ranked Kit

That is the correct recommend configuration if you have a single ranked match ram kit with a dual ranked matched kit which I can 100% confirm after testing.

do not mix dual ranked and single rank in the same channel it will cause random odd issues what might seem more like a driver issue or some odd hardware issue but you can work out why as all drivers etc are upto date and fresh install of O/S.

 

[35below0]

well after testing it appears that I had my system ram configure correctly I indeed need to keep the single ranked ram kit in slots A_1 and A_2 which is channel 1 and the Dual Ranked Ram Kit in Slots B_3 and B_4 which is channel 2.

I think you must have mis-understood me as your config advise for setting up mixed paired ram is incorrect but thanks anyway it's all sorted and running great at ddr 2667Mhz 1.35v with interleaving enabled

The correct confiuration when using matched a pair of single ranked Ram sticks and matched a pair of dual ranked Ram sticks is as follows (for people who maybe running in to issues)

slot1. A_1 (channel 1) Single ranked Kit
slot2. A_2 (channel 1) Single ranked Kit
slot3. B_3 (channel 2) Dual ranked Kit
slot4. B_4 (channel 2) Dual ranked Kit

That is the correct recommend configuration if you have a single ranked match ram kit with a dual ranked matched kit which I can 100% confirm after testing.

do not mix dual ranked and single rank in the same channel it will cause random odd issues what might seem more like a driver issue or some odd hardware issue but you can work out why as all drivers etc are upto date and fresh install of O/S.

Please show a picture from the user manual, or link to it's download. There isn't a MoBo in existance with B_3 and B_4 RAM slots.

As for your memory configuration issue, you should expect to lose some max performance when using 4 slots vs using 2 slots. If you're not hitting that max performance, you may not lose anything. But in general, when the motherboard has to deal with 4 RAM sticks, there are caveats and asterisks about RAM speed. esp. cheaper boards.

Consider yourself somewhat fortunate to be able to use mixed RAM kits without hiccups. Usually you'd have to check with the motherboard's QVL first.

 

[35below0]

Oh whoops sorry I'll correct that

slot1. A_1 (channel 1) Single ranked Kit
slot2. A_2 (channel 1) Single ranked Kit
slot3. B_1 (channel 2) Dual ranked Kit
slot4. B_2 (channel 2) Dual ranked Kit

You're mistaken about the channels. A_2 and B_2 are channel one, A_1 and B_1 are channel two. Unless the motherboard manual says otherwise, which is why i asked for a link or picture.

The RAM kits can work in any configuration, or they may fail to work in any possible configuration. And there is the best and fastest configuration possible. This is what Darkbreeze wrote.

If you're happy and your RAM works, you can just call it a day. No need to fight over this.

 

[The TrippyHippie]

Used mixed kits many times never had any major issues that were not resolved, but always good to brush up on what you know, many people dont have issues with mixed ram who dont overclock etc, there are most likely many PC /laptops running with unmatched ram fine and without issue, just how it is i guess.

 

[The TrippyHippie]

Just because you dont buy matched ram doent automatically mean they wont work.

If they work they work, just might not be the optimal configuration.

 

[Zerk2012]

man, those RAM sticks have been pull more times than a .... Lets not go there, but Ok and breath.

Please forgive oh holly Ram GODS for I have sinned mixing up the slot confing'f of A down to B and mistakinly give'f wrong info of much needed.

Disclamer : Not at any point did I say I know what i'm talking about.

I don't think anybody ever said mixing 4 sticks can't work.
You get 3 things.
1. it works.
2. you can make it work adjusting settings and/or voltage.
3. it just don't work.

Back with DDR2 it was pretty much just plug and play, DDR3 about the same as long as you weren't mixing low and high density, DDR4 got a bit more picky, DDR5 pickier than DDR4.

The main reason people recommend matched tested sets is because it was tested to work together. It would be bad to have 32GB and need 64GB so you buy another 32GB and it don't work together then you have wasted money and are right back from the start.

You can buy 4 individual sticks and you still have the same 3 possible outcomes.

 

[Darkbreeze]

well after testing it appears that I had my system ram configure correctly I indeed need to keep the single ranked ram kit in slots A_1 and A_2 which is channel 1 and the Dual Ranked Ram Kit in Slots B_3 and B_4 which is channel 2.

No, you don't. This is 400% wrong. But obviously you aren't going to listen. And, since you refuse to provide the model of your motherboard, you clearly don't want anybody to show you where you are going wrong either so good luck to you.

 

[Darkbreeze]

You're mistaken about the channels. A_2 and B_2 are channel one, A_1 and B_1 are channel two. Unless the motherboard manual says otherwise,

No man, this is wrong. A1 and A2 ARE one channel, but, you don't put both matched DIMMs from the same two DIMM kit in the same channel.

(Assuming you are using two separate kits, or trying to, rather than buying a single two DIMM kit that has the full capacity you need which is always the better idea, or a single kit with four matched DIMMs)

Doing that ensures that the board WON'T try to use those two sticks, together, in dual channel operation. Instead, it will try to use one UNMATCHED stick from each kit in dual channel AND that is where a lot of problems arise from.

Dual channel is what it sounds like DUAL channel. Not SINGLE channel. AND, for DUAL channel to work you are best off trying to use DIMMs that you KNOW are matched and have been tested together and found compatible from the factory in the population configuration for which the architecture was designed. You can put memory anywhere you want, but you might as well just be rolling the dice on the craps table, rather than doing what decades of engineers have found clearly determined works best. I even offered the exact reason for this, which of course was ignored, despite the fact that it comes from probably one of the absolute most knowledgeable memory people on this or any other forum for a great number of years especially since Tradesman1 passed away.

This, in a nutshell, is why.

From the electrical engineering point of view, the DRAM dies provide adjustable bus termination and putting the only active DIMM for each channel on each channel's last slot puts them at the end of the bus where those bus terminations will be most effective at mitigating signal reflections, which should give you the likely best chance at trouble-free operation - the 5mm unterminated bus stub from an unpopulated DIMM slot before the bus termination is less disruptive than a 10-15mm stub at the end of the bus from the extra PCB trace distance and connector.

Support for multiple DIMMs per channel almost got scrapped from the DDR4 spec due to such signal integrity concerns.

 

[Darkbreeze]

Memtest is not infallible. I have seen dozens of systems that could pass Windows memory diagnostic, Memtest86, Prime95, OCCT and other stability tests that are or have memory specific test routines, but the memory still ended up being the problem because replacing it entirely resolved the issue. So, it's a good tool, but it's only a tool.

Just like, an engine can pass compression tests with flying colors and still fail the next day due to low oil pressure which a compression test cannot tell you about.

 

[Darkbreeze]

It's ok. It's not just you. Like I said, a LOT of people make the same mistake and it is 100% due to the way they word things in the user manuals. I've even contacted all the major board manufacturers asking them to clarify their descriptions of the memory architecture channel configurations but of course they don't listen to me or do what I ask. The fact that the explanations of the channels is counter intuitive is balanced by the fact that basically every single user manual also has a CORRECT image showing the memory population rules.

Also, basically every memory manufacturer has a statement somewhere in their FAQ sections saying you should not mix memory that didn't come together in one kit and that the only way they actually "guarantee" memory to work is if their compatibility list shows it as compatible AND you aren't mixing it. They don't say it CAN'T work, and neither do I, but the fact is that in some cases it simply won't work, or will work but it will have problems, or in some cases the memory is similar enough (Ranks, rows, ICs, timings, voltage) that it just works without issue. But regardless of all that, making sure you use the correct DIMM slots is the #1 priority because unless you do that you are seriously hampering your chances that it will work properly.

In fact, for a lot of boards, even with two DIMMs that came together, if you put them in A1 and A2, B1 and B2 or in A1 and B1 without there already being DIMMs in A2 and B2, it will not work right.

 

[35below0]

No man, this is wrong. A1 and A2 ARE one channel, but, you don't put both matched DIMMs from the same two DIMM kit in the same channel.

I'm mixed up now. I thought A1 and B1 are one channel, controlled by one of two CPU controllers? Or are A1 and A2 one channel, but controlled separately by two controllers?

 

[The TrippyHippie]

as far as my old brain can remember you used to have two ways to get Dual channel mode us ing 2 sticks of ram and i think it was slots 2 and 4 was the fastest way and slots 1 and 4 was dual channel but i can remember lo was one config called asynchronous and the other dual channel way called synchronous?

It's been such a long time my brain is now cabbaged just trying to remember lol

Either way I now have 1 matched set in slots 1 and 4 and the other matched set in slot 2 and 3 gawd knows if thats correct but it's hasn't randomed out yet and it's gotten to point im beyond carring lol if its stable its stable, if it's not then soggy lentils to it.

 

[The TrippyHippie]

This motherboard provides four memory sockets and supports Dual Channel Technology. After the memory
is installed, the BIOS will automatically detect the specifications and capacity of the memory. Enabling Dual
Channel memory mode will double the original memory bandwidth.
The four memory sockets are divided into two channels and each channel has two memory sockets as following:
Channel A: DDR4_A1, DDR4_A2
Channel B: DDR4_B1, DDR4_B2

I had correct from the start
Note to self READ THE BLOODY MOTHERBOARD MANUAL IF IN DOUBT !