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Question 2x(2x8) GB single rank = 4x8 GB in dual rank?

VforV

Member
Oct 19, 2019
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Hey guys, I'm thinking of upgrading my 2x8GB DDR4 memory kit, by adding another identical kit of 2x8GB.

My current memory is Crucial Ballistix Sport LT 16Gb DDR4 3000 MHz CL15 (BLS2K8G4D30AESBK), which on crucial official description says it's SR (single rank).

If I add another kit, will it function as DR (dual rank)?

I'm looking to improve my 1% lows in games. As far as I've seen in tests it can get up to 10%-15% better 1% lows with 32GB dual rank memory.
Or should I just save the money for the GPU upgrade I plan later this year?
 

damian101

Senior member
Aug 11, 2020
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What's relevant is the number of ranks per channel. If those ranks are on different DIMMs or not makes pretty much no difference for performance afaik.
More ranks per channel increase load on the memory controller. If you have a Zen or Zen+ CPU you might not be able to reach the 3000MHz anymore, my 2700x goes up to 3066 MHz with two ranks per channel, the limit was much lower on earlier BIOS versions.
 

VforV

Member
Oct 19, 2019
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I have a Ryzen 2600, as in my signature.
All I know is that this model, listed above is dual channel, single rank 2x8GB 3000 CL15. And I would like to get the same model, not a different one because that will cause other problems - mixing different models of ram...
 

damian101

Senior member
Aug 11, 2020
276
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I have a Ryzen 2600, as in my signature.
All I know is that this model, listed above is dual channel, single rank 2x8GB 3000 CL15. And I would like to get the same model, not a different one because that will cause other problems - mixing different models of ram...
Adding those two sticks will give you the same performance benefits dual rank memory has.
Just know that you might not be able to reach the full 3000 MHz anymore. On an old BIOS you definitely won't be able to reach the 3000 MHz. And with old I mean pre-Zen2, somewhere around that time a new AGESA version was rolled out that dramatically increased RAM stability with my 2700x.
 

VforV

Member
Oct 19, 2019
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9
16
@damian101
My MB is MSI B450M Mortar Max with the latest BIOS update, I did it 1 month ago.
My ram kit is OC now at 3600Mhz, but not great timings, I think CL19. It's still faster than stock 3000MHz CL15.

My concern is if one kit is single rank adding another identical kit makes the system work as dual rank? Since that's the only way I'll get more performance for the 1% lows...
 
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MalVeauX

Senior member
Dec 19, 2008
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Heya,

I think it matters if your motherboard's memory topology is t-topology or daisy chain before you'll be able to realize the gains you're looking for using 4 sticks and worrying about their ranks and the density of the sticks themselves. Also those gains are rather specific to only a handful of titles, and even then, generally only if the GPU is not higher end and so the CPU/Memory gets to be a bottle neck.

General wisdom is if you want to improve gaming performance, max out your GPU potential before you try to upgrade your CPU/Memory as if it were some bottleneck. If your games are being run at low resolution with low quality settings, then you are indeed inducing a bottleneck at the memory and CPU as latency is what matters here (less so much raw speed, fast sounds great unless its waiting its turn to do something due to high latency). You'll get far more improvements in gaming FPS with higher resolution and quality settings with a GPU upgrade.

Focusing on memory/CPU for that last 1% type stuff is for when you're already on the top end GPU that you can afford or even get and you're just interested in the exercise of maximizing memory speed/latency balance on a system and measuring it. Otherwise, you'd never know at all that it existed because people are spending more time doing this than playing their games at this point just out of it being a hobby.

Very best,
 

VforV

Member
Oct 19, 2019
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@MalVeauX You're right, GPU upgrade is priority no.1, but it's also the single most expensive upgrade in a PC... upgrading memory is a fraction of that cost. My next GPU upgrade is about $400+, but for memory about $60-80.

Anyway, I have found my answer in a different forum and I know now I can't make 2 kits of single rank memory work as dual rank, just because they are 2 instead of 1.

As for motherboard's memory topology, I think mine is Daisy Chain, but how would I check that I have no idea. I just compared it by looks.
This is my MB > https://www.msi.com/Motherboard/B450M-MORTAR-MAX/Gallery#lg=1&slide=1
And I used this to compare > https://www.techpowerup.com/review/amd-ryzen-memory-tweaking-overclocking-guide/4.html

Edit: I just found out this video, is he correct?
 
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VforV

Member
Oct 19, 2019
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9
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Can anyone confirm what Steve from HU is saying here? Adding 2 more stick of SR with the already 2 makes the 4 sticks work in DR? Because this is why I would upgrade and buy 2 more...
 

MalVeauX

Senior member
Dec 19, 2008
618
149
116
Heya,

Take note that as you move through the first half of the video, it hypes you into thinking if you just put 4 sticks on your AM4 board with Ryzen you'll get an instant boost in performance. Even if it's single rank, high density, with loose timings, and they don't even talk about the memory topology of the board (which matters a lot). So then, after that, in the last half, you start seeing titles showing a very little to no significant difference with the single/dual rank differences and so no difference stacking in 4 sticks. Only some titles benefit from having the 4 sticks. Many do not. That's the take away. And the only way to even see these increases was to run the game low resolution so that the GPU would be bottlenecked by the CPU/Memory of the system.

And they're not using cheap RAM. And they're manually tweaked to be as fast as they could... on Trident Z stuff. This stuff costs as much as a new lower mid-tier GPU.

You have to compare the cost of this extra RAM (they're using good RAM, pricey) versus the cost of a newer better GPU running high res with all the bells & whistles enabled.

Bottom line, buy more RAM and double it up and see for yourself and report back with averages of your performance changes. But don't do it if the cost of your GPU & new RAM = new GPU that is better.

Very best,
 
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VforV

Member
Oct 19, 2019
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Bottom line, buy more RAM and double it up and see for yourself and report back with averages of your performance changes. But don't do it if the cost of your GPU & new RAM = new GPU that is better.
You are correct in all you are saying, but I asked this here 1st especially to not do what you just said. I don't want to "test" things with my money, so I was hoping someone else has already done that or just knows how this works.
Anyway, I get it now.
 
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MalVeauX

Senior member
Dec 19, 2008
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You are correct in all you are saying, but I asked this here 1st especially to not do what you just said. I don't want to "test" things with my money, so I was hoping someone else has already done that or just knows how this works.
Anyway, I get it now.
I hear ya,

I'm interested too.

While there's plenty of videos out there from big channels showing that high quality fast RAM with tight timing and low latency can improve performance in some games, it doesn't show much for anything else for productivity or anything, a few benches for synthetics, but the key is that they're using top shelf RAM on good motherboards. So it's a skewed piece of information towards higher end components. But I suppose the target is, if you're trying to get the last bit of performance out of a system to the point where you're looking at optimizing memory on the system, then you've likely already gotten the most you can out of your GPU, CPU, SSD, etc, and so you're already maxed out there (for cost) and so you're just looking to the other components now...

A very interesting test would be to use an average motherboard with run of the mill daisy chain memory topology with average tier cost RAM (likely single rank) and see if the benefits of going from 2 sticks of high density to 4 sticks of lower density memory, with fairly good speed (3200mhz to 3600mhz) and fair latency in the CL16 to CL18 range with 1:1 infinity clock coupling would produce similar gains in some game titles, or if it wouldn't make a big enough difference, and how it performs in productivity applications or synthetic benches.

Very best,
 
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VforV

Member
Oct 19, 2019
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Well, I guess I found out my answer after more digging and info, both from here and outside of the forum.

The answer is that, yes, adding 2 more sticks will make them (all 4) work as dual rank, but the benefits depend on the game and the quality of the ram kits (speed and timings).

So at this time, I think is not worth it to spend money on this memory upgrade. I'll focus on upgrading the GPU and then CPU (when the prices get reasonable). Thank you.
 
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