Question 2x "single" RAM sticks vs. a kit of 2x "dual" RAM sticks

[otringal]

I'm close to buying my new 2x16GB modules, however I'm a bit skeptical over the following thing:

Before going any further, I KNOW what everyone out there says: "there's no such thing as dual channel modules, you only need to make sure your modules have the same specs so that the motherboard can run them as dual channel, hence the only small advantage kits have is that they're tested for compatibility with each other before shipping them, bla bla bla bla", but I can't help but notice that ALL (and I mean all) RAM brands/manufacturers out there have different serial/part numbers for single-channel modules vs. dual-channel modules. And that's a bit suspicious. I mean... if a kit is nothing more than 2x "single" modules tested together for compatibility and packaged together inside the same box, then why would they go through all the trouble of labelling these modules separately with different bar codes and product numbers, as well as listing them under different tables/places in their catalogs?

I'm still not sure that 2x "single" modules are just as good as a kit of 2x "dual" modules... And since I can't find ANY local kits for sale at the moment (ordering online has a waiting time of up to 2 weeks ), I was able to find a ton of "single" modules. So I'm basically wondering just how much am I risking if I'll buy 2x modules from the same vendor, at the same time, with obviously the same brand model and specs. Factory-wise they might not be 100% produced one after another (obviously), but also I don't think they'd be that far apart... there should be some correlation between the manufacturing and shipping processes when talking about 2 modules which ended up for sale at the same shop, most likely coming in in 1 lot/shipment. But I'm still scared enough not to fall into a similar case I have at the moment, where they'll "misbehave" when running at the same time and the vendor would then say "well... sorry... it's your fault for not getting a proper kit, therefore no money back policy for you, mister!" 😞

 

[rgd1101]

always buy a kit as they are tested together.
not who said no such thing as dual channel modules. if you go thru the forum you see more people having issue with stick vs kit.

 

[DRagor]

vendor would then say

When buying RAM as single sticks just make sure vendor you chose has good return policy, that's all you really need. I mean it does not matter if the failure of matching rate is 10% or 90%, in either case you can be the unlucky one to get two sticks that just don't match no matter what you do. And then all you can do is return the sticks and get another two and hope for better result.

 

[Endre]

I'm close to buying my new 2x16GB modules, however I'm a bit skeptical over the following thing:

Before going any further, I KNOW what everyone out there says: "there's no such thing as dual channel modules, you only need to make sure your modules have the same specs so that the motherboard can run them as dual channel, hence the only small advantage kits have is that they're tested for compatibility with each other before shipping them, bla bla bla bla", but I can't help but notice that ALL (and I mean all) RAM brands/manufacturers out there have different serial/part numbers for single-channel modules vs. dual-channel modules. And that's a bit suspicious. I mean... if a kit is nothing more than 2x "single" modules tested together for compatibility and packaged together inside the same box, then why would they go through all the trouble of labelling these modules separately with different bar codes and product numbers, as well as listing them under different tables/places in their catalogs?

I'm still not sure that 2x "single" modules are just as good as a kit of 2x "dual" modules... And since I can't find ANY local kits for sale at the moment (ordering online has a waiting time of up to 2 weeks ), I was able to find a ton of "single" modules. So I'm basically wondering just how much am I risking if I'll buy 2x modules from the same vendor, at the same time, with obviously the same brand model and specs. Factory-wise they might not be 100% produced one after another (obviously), but also I don't think they'd be that far apart... there should be some correlation between the manufacturing and shipping processes when talking about 2 modules which ended up for sale at the same shop, most likely coming in in 1 lot/shipment. But I'm still scared enough not to fall into a similar case I have at the moment, where they'll "misbehave" when running at the same time and the vendor would then say "well... sorry... it's your fault for not getting a proper kit, therefore no money back policy for you, mister!" 😞

Hello!

The thing this:
•If you buy 2 identical individual memory modules and run them at default JEDEC speed, you'll have no issues.
•But, if you want those high speeds that can only be obtained through XMP (memory overclock), then you should go with a kit, because the DIMMs have been tested together at those speeds and they're working well.

 

[otringal]

When buying RAM as single sticks just make sure vendor you chose has good return policy, that's all you really need. I mean it does not matter if the failure of matching rate is 10% or 90%, in either case you can be the unlucky one to get two sticks that just don't match no matter what you do. And then all you can do is return the sticks and get another two and hope for better result.

Good point, but are you saying there are still some small chances of having an actual kit and still encounter issues? Like, did that ever happen?

Hello!

The thing this:
•If you buy 2 identical individual memory modules and run them at default JEDEC speed, you'll have no issues.
•But, if you want those high speeds that can only be obtained through XMP (memory overclock), then you should go with a kit, because the DIMMs have been tested together at those speeds and they're working well.

As far as I've seen, only a few brands of RAM have XMP profiles, especially for laptops. Most of them only have JEDEC compatibility and that's it. Are you saying that such modules are safe to use even if they don't come as a kit, since there won't be problems if using them with the JEDEC profiles? I'm asking because that's precisely what I'm trying to fix right now, I have 2x ADATA modules which are perfectly fine by themselves, but fail to play nice when running together (at a normal JEDEC spec, obviously).

 

[DRagor]

but are you saying there are still some small chances of having an actual kit and still encounter issues?

If you buy a kit then you should not run into compatibility problems. Still, even then you can run into DoA sticks, or your motherboard may do not want to play nice with them (the latter is especially possible in case of 4 stick kits).

 

[SyCoREAPER]

As others said, don't gamble it. Why subject yourself to potential issues by not buying a kit?

Do it once, do it right.

That aside, you 'should' be OK mixing same JEDEC speed RAM, XMP is definitely above gamble, odds against you. Even if it boots and seems to work, you might face stability or degraded performance.

 

[Endre]

Good point, but are you saying there are still some small chances of having an actual kit and still encounter issues? Like, did that ever happen?



As far as I've seen, only a few brands of RAM have XMP profiles, especially for laptops. Most of them only have JEDEC compatibility and that's it. Are you saying that such modules are safe to use even if they don't come as a kit, since there won't be problems if using them with the JEDEC profiles? I'm asking because that's precisely what I'm trying to fix right now, I have 2x ADATA modules which are perfectly fine by themselves, but fail to play nice when running together (at a normal JEDEC spec, obviously).

Hello!

I'm not so sure about laptops, because they tend to use specific hardware.
But on desktop PCs, I've never encountered issues with dual single DIMMs of the same model running in dual-channel mode at JEDEC speed.

Still, weird things can happen if the motherboard is really cheap, or if the memory is from an un-trustworthy brand, or if it's a bad BIOS version.

 

[otringal]

Ok... I finally managed to fix my problem. And ironically, using ADATA memory - the same brand which didn't work initially. Long story short: I changed the modules with some others, but the difference is that the ones which did not work have the package number AD4S320032G22-BGN, while the ones that did work are AD4S320032G22-SGN. A quick lookup on ADATA's website reveals that the only difference is that B means Bulk, why S means Single Tray, along with the other options (R - Retail and DT - Double Tray), which I haven't tried. Apart from this general package number, all my Bulk SO-DIMMs have their individual serial numbers (the small labels stuck on the chip dies themselves) starting with 2Mxxxxxxxxxx, while the Single Tray ones start with 1Mxxxxxxxxxx. And I've tested a whole batch of modules.

Therefore, I'll have to come back to my earlier questions about packaging serial numbers: if the only thing that would differ would be the way in which they get packaged, and therefore offer some cost saving solution for Bulk for example, when compared to the others, than:

1. why would they go through the extra trouble of labelling them differently (both the package and the chips themselves) and also separate them in the catalog by different categories?
2. why would the Bulk ones exhibit problems, while the Single Tray ones be just fine (I didn't even need Double Tray which is the equivalent of a dual-channel kit)?

There's clearly a difference somewhere in the manufacturing process, they cannot be simply manufactured on the same assembly line, with the same specs, at the same location, from the same materials, one after another in identical batches and then get randomly selected for being a B, R, S or DT version. I remind you that the Bulk ones are not faulty SO-DIMMs, they work perfectly well by themselves, but my MSI rejects them if they're both running at the same time. And I tested 7 modules in different pairs/combinations, the results were always the same.