Question Corsair: Mixing 2 identical kits of 2x16GB DDR5

[engmike]

Hello all,


I'm located in Egypt, and I couldn't find any Corsair DDR5 sold here.
So, I decided to buy them from the US and have one of my friends bring them to me.
I couldn't find any kit that is 4x16GB in the US (or at least as far as I searched).
So, I already bought 2 kits of "CMH32GX5M2B5200C40" of 2x16GB ) totaling 64GB (see the images).
First kit sticks are ver. 4.43.02 and the second kit sticks are ver. 3.43.01
I already received the first kit in Egypt and it's working as it should.
The second kit is still currently with another friend in the US, and he'll be bringing it to me in Egypt soon.
Now, that you have seen both kits, I'm looking for an insight and specific technical support to my case.

My PC configurations are:
-MB: ASUS ROG STRIX Z690-E GAMING WIFI
-CPU: Intel Core i5-12600K
-GPU: ASUS ROG STRIX RTX 3050 OC 8GB

What actually would happen when I use them both in my system? Please I need specific and personalized answer to my specific situation.

Do both kits have the same chips (how to verify)? what are the differences between both versions? should I return the second (not yet received in Egypt) kit to avoid and instability/crashes issues?

I'm asking this because I'll have no chance in returning the second kit once it's here in Egypt, so I need to make sure that it'll work perfectly with my first received working kit.

Thanks for your patience replying to all of my questions.

Regards.

 

[Lafong]

"what actually would happen"?

I don't think you can get a definite answer without testing once all 4 sticks are in hand.

You could try Corsair customer service, but that may well be laughable.

You can get all types of speculation, including no issues at all.

I wouldn't expect anything dangerous to other components.

I assume you are unable or unwilling to buy a kit of two sticks, with 32 gb per stick; total of 64.

All 4 sticks could easily "work", but not at expected speeds. I have no idea how you would react to that.....maybe having all 64 gb recognized is all you want, regardless of speed.

"The second kit is still currently with another friend in the US, and he'll be bringing it to me in Egypt soon."..............is it even known that these sticks are not DOA or problematic on their own, disregarding compatibility with the 2 you now have in Egypt?

 

[DRagor]

I'm asking this because I'll have no chance in returning the second kit once it's here in Egypt, so I need to make sure that it'll work perfectly with my first received working kit.

Since there is absolutely no way to ensure two kits will work perfectly (especially on DDR5) I advise to return them now. The whole point with mixing kits is you never know if they will work or not. If you can return it's no big deal as there is always a chance a replacement pair of stick could work just fine. But in your situation it's just unnecessary risk.

 

[engmike]

"what actually would happen"?

I don't think you can get a definite answer without testing once all 4 sticks are in hand.

You could try Corsair customer service, but that may well be laughable.

You can get all types of speculation, including no issues at all.

I wouldn't expect anything dangerous to other components.

I assume you are unable or unwilling to buy a kit of two sticks, with 32 gb per stick; total of 64.

All 4 sticks could easily "work", but not at expected speeds. I have no idea how you would react to that.....maybe having all 64 gb recognized is all you want, regardless of speed.

"The second kit is still currently with another friend in the US, and he'll be bringing it to me in Egypt soon."..............is it even known that these sticks are not DOA or problematic on their own, disregarding compatibility with the 2 you now have in Egypt?

Thanks for your reply.

These are 5200MHz memory, and my CPU is already maxed out at 4800MHz, as per this:

Intel® Core™ i5-12600K Processor (20M Cache, up to 4.90 GHz) Product Specifications

Intel® Core™ i5-12600K Processor (20M Cache, up to 4.90 GHz) quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.

ark.intel.com

So, I guess that the memory shall work OK on 4800MHz as this would be like I'l downclocking them, yes?

As for knowing if they are DOA on their own, I'll never know..but I don't think it's going to be an issue, I already bought all of the MB, CPU, NVMe, RAM from the US with no issues at all.

 

[engmike]

Since there is absolutely no way to ensure two kits will work perfectly (especially on DDR5) I advise to return them now. The whole point with mixing kits is you never know if they will work or not. If you can return it's no big deal as there is always a chance a replacement pair of stick could work just fine. But in your situation it's just unnecessary risk.

Thanks for your reply,

But the issue is that I need 64GB of RAM, and this model is not found here in Egypt.
Do you have anyway to know what are the real difference between ver. 4.43.02 and ver. 3.43.01? Is there a way to know in the first place? I tried to reach out to Corsair customer support, but no reply till now.

Knowing that my CPU can handle DDR5 RAM up to 4800MHz as per:

Intel® Core™ i5-12600K Processor (20M Cache, up to 4.90 GHz) Product Specifications

Intel® Core™ i5-12600K Processor (20M Cache, up to 4.90 GHz) quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.

ark.intel.com

And knowing that these modules are 5200MHz, so I'll be downclocking them to match the CPU maximum capability, will this be a solution?

 

[DRagor]

Do you have anyway to know what are the real difference between ver. 4.43.02 and ver. 3.43.01?

Does not matter. Even if both were 4.43.02 there would still be no guaranty they would work together.

Knowing that my CPU can handle DDR5 RAM up to 4800MHz

Does not matter what CPU can handle, if motherboard can handle faster RAM then CPU can too. Limiting RAM to 4800 will actually hurt your performance. And again, there is no way to tell what will happen, even when using only 4800 speed.

And DDR5 does not really work well with 4 sticks in first place. If you really need 64 GB then buy 2x32GB kit. There is no other way to ensure it will work properly without problems.

 

[DSzymborski]

The versioning doesn't matter. The sticks can be manufactured identically minutes apart and be functionally different. They don't produce different individual sticks of RAM; it's a binned product. RAM is labeled based on, essentially, how defective the manufacturing is. No two RAM sticks are actually identical; it's just that the ones packaged together are tested to work together anyway. CPUs are similiarly produced. It's a limitation of semiconductor fabrication.

It's not like, say, car manufacturing. Honda makes separate Accords and Civics. Civics aren't just Accords that are too defective to be called Accords.

 

[engmike]

The versioning doesn't matter. The sticks can be manufactured identically minutes apart and be functionally different. They don't produce different individual sticks of RAM; it's a binned product. RAM is labeled based on, essentially, how defective the manufacturing is. No two RAM sticks are actually identical; it's just that the ones packaged together are tested to work together anyway. CPUs are similiarly produced. It's a limitation of semiconductor fabrication.

It's not like, say, car manufacturing. Honda makes separate Accords and Civics. Civics aren't just Accords that are too defective to be called Accords.

I was told that ver. number will indicate what type of chips are on the module, so basically same ver. numbers indicate identical RAM modules and chips manufacturer, so theoretically same ver. number kits will work together.

So, you recommend to return the new undelivered RAMs? no other way to make use of my 4 DIMMs unless I buy a 4 modules kit?

 

[USAFRet]

So, I guess that the memory shall work OK on 4800MHz as this would be like I'l downclocking them, yes?

I recently tried almost exactly this.

Corsair Vengeance LPX
Originally, 2x 16GB (32GB)

Add 2x 32GB (64GB)

So, 96GB total, right?

System booted up just fine.
After about 5 minutes, ethernet cuts out.

Swapping the 2 pairs between slots 1-3 and 2-4...no combination would give a stable result.

Each pair on its own works just fine, in any slot pair.

Currently just on the 2x 32GB.

 

[engmike]

Does not matter. Even if both were 4.43.02 there would still be no guaranty they would work together.

Does not matter what CPU can handle, if motherboard can handle faster RAM then CPU can too. Limiting RAM to 4800 will actually hurt your performance. And again, there is no way to tell what will happen, even when using only 4800 speed.

And DDR5 does not really work well with 4 sticks in first place. If you really need 64 GB then buy 2x32GB kit. There is no other way to ensure it will work properly without problems.

Technically; if both are 4.43.02 they will work I assume, cause ver. number indicates same chips and timing and everything, so why wouldn't they work together?

For the CPU; do you mean that no matter the max RAM speed, the CPU would handle even if it's maxed out at 4800MHz?

And you mean that it's not the best solution to even buy 4 sticks kit because DDR5 is not the best in 4 sticks? then how do I make use of my 4 DIMMs in my MB? if installing a 4 sticks kit is not a good choice, then why would MB manufacturers put 4 DIMMs slots in the first place?

 

[Lafong]

no other way to make use of my 4 DIMMs unless I buy a 4 modules kit?

No one has said that.

You can try when all 4 are in Egypt. You won't know until you try.

Does "make use" mean "64 GB recognized and usable without regard to speed or expectations"?

Or something else?

 

[engmike]

No one has said that.

You can try when all 4 are in Egypt. You won't know until you try.

Does "make use" mean "64 GB recognized and usable without regard to speed or expectations"?

Or something else?

make use means using all of the 4 DIMMs to total 64GB stable and usable, because I couldn't find a 4x16 kit, and if I bought 2x32 kit, then I won't be using the 4 DIMMs too...that's just so stupid of DDR5!!

 

[engmike]

I recently tried almost exactly this.

Corsair Vengeance LPX
Originally, 2x 16GB (32GB)

Add 2x 32GB (64GB)

So, 96GB total, right?

System booted up just fine.
After about 5 minutes, ethernet cuts out.

Swapping the 2 pairs between slots 1-3 and 2-4...no combination would give a stable result.

Each pair on its own works just fine, in any slot pair.

Currently just on the 2x 32GB.

So basically you would recommend to just stick to using 2 DIMMs whether it's 2x16 or 2x32..yes?

 

[USAFRet]

So basically you would recommend to just stick to using 2 DIMMs whether it's 2x16 or 2x32..yes?

I would recommend a set.
Either 2x or 4x, in whatever capacity you need.
No mixing, even if they are otherwise "identical".

Since you can't find 4x 16GB, then the 2x 32GB is the answer.

There is no benefit in having all 4 slots populated, even if it did work.

 

[DRagor]

Technically; if both are 4.43.02 they will work I assume, cause ver. number indicates same chips and timing and everything, so why wouldn't they work together?

Because even same chips/same timings are not exactly same. DSzymborski explained it in detail few posts above why it does not work.

For the CPU; do you mean that no matter the max RAM speed, the CPU would handle even if it's maxed out at 4800MHz?

Correct. CPU max speed has no effect on how fast RAM you can use.

And you mean that it's not the best solution to even buy 4 sticks kit because DDR5 is not the best in 4 sticks?

DDR5 is new. Because of that there is a lot of 'infancy' problems with it. One being 4 sticks don't work as well as 2. For now, it will be corrected later.

then how do I make use of my 4 DIMMs in my MB?

You don't. There is absolutely no need to use 4 slots just because there are 4. If they were Quad channel then yes, it would make sense because you would get better performance. But since it is only Dual channel there is no performance difference between 2 and 4 sticks. Actually, for now using 4 sticks you can expect worse performance then when using just 2.

if installing a 4 sticks kit is not a good choice, then why would MB manufacturers put 4 DIMMs slots in the first place?

Lots of reasons. For example you can treat them as 'spare' slots in case of main slots stop working - then you don't have to quickly swap mobo if something happens, you can just use the other pair. Another reason is as the DDR5 system matures using all 4 slots may become less risky then now. Yet another reason is for those that need absolutely gigantic amounts of RAM - since amount per stick is limited increasing number of slots is the only way to make that happen. But yes, for an average user two slots would be absolutely enough.

 

[engmike]

I would recommend a set.
Either 2x or 4x, in whatever capacity you need.
No mixing, even if they are otherwise "identical".

Since you can't find 4x 16GB, then the 2x 32GB is the answer.

There is no benefit in having all 4 slots populated, even if it did work.

OK, understood.
But why do you say "There is no benefit in having all 4 slots populated, even if it did work."? can you elaborate more on that?

 

[USAFRet]

OK, understood.
But why do you say "There is no benefit in having all 4 slots populated, even if it did work."? can you elaborate more on that?

64GB is 64GB.
Either 2x 32GB or 4x 16GB.

Having all 4 slots populated does not make it better or faster.

 

[Deleted member 2947362]

Another reason to why motherboards have 4 slots is so you can maximise the amount of RAM
One reason people can have an issue when all 4 slots are populated is the CPU memory controller has to a lower the speed of the RAM to what ever the CPU's Memory controller manufacturer officially supports.

for example with AMD and my CPU (the R means how many ranks the stick of RAM has and config supported)

Two ram slot support max ram speed

2x1R DDR4-3200
2x2R DDR4-3200

4 slot support max ram speed

4x1R DDR4-2933
4x2R DDR4-2667

Intel will have there official supported configs as well when using all four slots for their CPU's

And by adding mixed IC's (unmatched ram) it will be hard to say if it will work, depends if the memory controller can handle the speed/rank and all slots used while going above the official supported RAM speed, memory rank and slot configs.

Anything above the official support would be classed as an overclock and out of official spec (and probs Void the warranty on the CPU)

I not an expert but from my playing around I found the following

R1 sticks of ram overclock better/higher speed than R2 sticks of RAM because the memory controller has to work harder when using R2 sticks of RAM

If you want to know what your RAM kits are, R1 or R2 kits use CPU-Z to find out, It's also not recommended to use/mix R1 kits with R2 kits.

 

[geofelt]

From a performance point of view, realize that current intel and amd run ram in dual channel mode, regardless if populated with 2 or four sticks.
What can you expect?
I would expect the ram to work at default speeds.
No guaranteed.
You may want to enlist the aid of a knowledgeable person to try to set the ram parameters so things will work as best as possible.
When done, the test will be at least a full pas on memtest:
Run memtest86 or memtest86+
They boot from a usb stick and do not use windows.
You can download them here:

MemTest86 - Official Site of the x86 Memory Testing Tool

MemTest86 is the original self booting memory testing software for x86 and ARM computers. Supporting both BIOS and UEFI, with options to boot from USB.

www.memtest86.com

Memtest86+ | The Open-Source Memory Testing Tool

Memtest86+ is an advanced, free, open-source, stand-alone memory tester for 32- and 64-bit computers (UEFI & BIOS supported)

www.memtest.org

If you can run a full pass with NO errors, your ram should be ok.

Running several more passes will sometimes uncover an issue, but it takes more time.
Probably not worth it unless you really suspect a ram issue.

 

[Misgar]

If you end up with two sets of DIMMs, install one pair, download Thyphoon Burner and read out the contents of the SPD chip on each DIMM in turn.

Thyphoon Burner normally shows the manufacturer's name for the memory chips. In the picture below, it's Micron Technology, but it could be Samsung or Hynix.

Under Organization you can see these chips are set up as '2048M x64 (1 rank)'. Your DIMMs might be dual rank. Mixing single and dual rank dimms is undesirable.

Remove the first pair of DIMMs and fit the second pair. Run Thyphoon Burner again and check the new memory chips. If you're lucky the chip manufacturer will be the same and the rank organization will be the same too.

https://softnology.biz/files.html

This doesn't mean the memory chips are from the same batch, but they'll be slightly less "mismatched" than one pair with Hynix chips and another pair with Samsung chips. The closer the match between the two pairs, the better.

If you do fit four DDR5 DIMMs, forget XMP/DOCP overclocking and test the system at a really low speed, e.g. 4,000MHz. Booting up from a MemTest86 USB memory stick is a good way to check stability.

If your system passes a full run of MemTest86 at 4,000MHz, increase the RAM speed to 4,200MHz and test again. Continue to increase the memory speed in small steps, testing each time, until Windows crashes (BSOD) or the computer fails to boot. Reduce the memory speed and keep your fingers crossed.

Good luck.