Is 4x8gb or 2x16gb of ram better?

[Josh -_-]

Hey so i was wondering which would be better value. I'm using a 5600x and 3060 ti, and would just like to know which would be better. Thanks

[Skiiwee29]

Both will perform the same overall as long as the 2x16 is Dual ranked sticks and not single ranked. That said, Ryzen CPUs generally prefer and are more stable with 2x over 4x. 

[Josh -_-]

1 minute ago, Skiiwee29 said:

Both will perform the same overall as long as the 2x16 is Dual ranked sticks and not single ranked. That said, Ryzen CPUs generally prefer and are more stable with 2x over 4x. 

What are dual ranked sticks?

[Helpful Tech Witch]

1 minute ago, Josh -_- said:

What are dual ranked sticks?

weird. I think it has something to do with memory bandwidth, something like dual rank sticks have 128bit buss width, single is 64bit bus width, but im not sure

in general theyre a bit faster than single rank, but 2x dual rank is the same thing as 4x single rank.

[porina]

At same speed: 4x8 SR = 2x16 DR > 2x16 SR

 

Rank refers to one of the characteristics of the ram, which is unfortunately rarely specified. Loosely speaking to get higher capacity, you need either higher density chips, or more of them arranged into ranks. Modern 8GB modules are all single rank. 16GB modules up to a year or so ago were mostly dual rank, but they are trending towards single rank now. No experience of 32GB modules but I'd assume they're still dual rank.

 

More ranks can help with getting more useful effective performance out of ram. Downside is they are more load on the memory controller, so if you're running high speed kits there is higher chance they might not work at those higher speeds. Similarly for overclocking.

[Josh -_-]

7 minutes ago, porina said:

At same speed: 4x8 SR = 2x16 DR > 2x16 SR

 

Rank refers to one of the characteristics of the ram, which is unfortunately rarely specified. Loosely speaking to get higher capacity, you need either higher density chips, or more of them arranged into ranks. Modern 8GB modules are all single rank. 16GB modules up to a year or so ago were mostly dual rank, but they are trending towards single rank now. No experience of 32GB modules but I'd assume they're still dual rank.

 

More ranks can help with getting more useful effective performance out of ram. Downside is they are more load on the memory controller, so if you're running high speed kits there is higher chance they might not work at those higher speeds. Similarly for overclocking.

So you can't actually tell if it is dual or single ranked? 

https://au.pcpartpicker.com/product/33WBD3/ 

https://au.pcpartpicker.com/product/WH9tt6/corsair-vengeance-rgb-pro-16-gb-2-x-8-gb-ddr4-3600-cl18-memory-cmw16gx4m2z3600c18

Because these are the 2 i'm looking at buying, either 2x8 or 2x16. So which is better value?

Edit; and this one. https://au.pcpartpicker.com/product/33WBD3/

[Chris Pratt]

Optimal number of sticks always equals the number of channels. Since consumer systems are dual channel, that means two sticks. Four sticks just makes the IMC have to work harder.

 

When it comes to ranks, Ryzen prefers four total, which can be achieved with either two dual rank or four single rank. Unfortunately, RAM manufacturers almost never actually advertise what rank their modules are. If you do see something like 2Rx8, 1Rx16, etc., the first part is the rank. The second part is the density, which actually does matter for performance as well. Lesser density is better, so x8 is preferable to x16, but density is usually hidden even better than rank.

 

You can also just search online for the particular kit you're considering and add the term "rank" to your query. You'll often find a forum or Reddit post where people will tell you. You can also tell on the label, generally, if you have it physically in hand.

 

[porina]

9 hours ago, Josh -_- said:

So you can't actually tell if it is dual or single ranked?

It is easy to tell after you have received the module and you can run software to read it out. CPU-Z can work most times, Thaiphoon Burner has a higher chance of working.

 

Of course that doesn't help if you need to know which to buy in the first place. Next best thing to do is search for the exact part and find a reviewer who might have determined the rank.

 

Of the listed kits, I can say the kit with 8GB modules will be single rank. Only some very early DDR4 8GB modules were dual rank. Haven't been that way for a long time. I have a compute use case that responds strongly to ram performance. In that use case, a dual rank 3200 kit can significantly outperform a single rank 3600 kit, and this applies to both Intel and AMD systems.

 

Using 4 single rank modules (e.g. 8GB) in a dual channel system is one way to guarantee having effectively 2 ranks per channel. Strictly speaking rank is internal to a module, so using two modules is more correctly 2 DIMMs per Channel (2DPC). In terms of performance, as far as my testing is concerned, it works exactly the same as a single dual rank module.

[CamoGeko]

So, lets say I have 8GBx2 right now if I put 8GBx2 more into my system will CPU-Z show that I am effectively running in Dual-Rank? 

[aDoomGuy]

11 minutes ago, CamoGeko said:

So, lets say I have 8GBx2 right now if I put 8GBx2 more into my system will CPU-Z show that I am effectively running in Dual-Rank? 

No I don't think so. Not sure however..

[CamoGeko]

49 minutes ago, aDoomGuy said:

No I don't think so. Not sure however..

Thanks, pretty much what I was thinking since it shows details of each module individually.