DDR5 - is there ANY advantage to using 4 sticks instead of 2 - other than looks...?

[NGamer]

DDR5 - is there ANY advantage to using 4 sticks instead of 2 - other than looks...?

 

I have seen one of Linus' YouTube videos where he says that using (2) 32 GB (64 GB) sticks of RAM - instead of (4) 16 GB (64 GB) of RAM is easier on the CPU's memory controller...?

[Fasauceome]

If you buy single rank dimms, four will give you a dual rank setup. Memory Rank is not often talked about in PC upgrade discussions, especially because you won't see it advertised on the store page for memory, but in memory sensitive applications it might improve performance by like 10%.

 

On the other hand, it is easier on the memory controller to use less dimms, but that typically becomes more of a concern with very high speeds.

 

Edit: I also recall early Intel 12th gen issues with 4-dimm compatibility. Even with quad kits, systems would fail to post quite a lot. Not sure if those have been ironed out by now.

Edited July 22, 2022 by Fasauceome

[Hairless Monkey Boy]

For DDR5, it's even worse, there are only disadvantages to using 4 sticks rather than 2. At least according to the last video of Buildzoid's that I saw on the subject.

 

There is a significant speed penalty to using 4 sticks instead of 2.

[RONOTHAN##]

9 minutes ago, Fasauceome said:

If you buy single rank dimms, four will give you a dual rank setup. Memory Rank is not often talked about in PC upgrade discussions, especially because you won't see it advertised on the store page for memory, but in memory sensitive applications it might improve performance by like 10%.

On DDR5 the advantage is extremely minimal, basically only Geekbench scales with dual rank compared to single rank on DDR5, and even then not by all that much. the main advantage of dual rank on DDR4 and earlier was 8 bank groups per channel instead of 4, on DDR5 where you already have 8 bank groups per rank you're approaching the limits of what the memory controller can interleave anyway the difference is very small. It's more equivalent to running quad rank DDR4 compared to dual rank DDR4, yeah there's more ranks to interleave but the memory controller can't really take advantage of it and you lose out on max frequency since the memory controller can't keep up. 

 

18 minutes ago, NGamer said:

I have seen one of Linus' YouTube videos where he says that using (2) 32 GB (64 GB) sticks of RAM - instead of (4) 16 GB (64 GB) of RAM is easier on the CPU's memory controller...?

It's not really that it's easier on the CPU's memory controller, it's more that it's easier on the motherboard's memory topology. All the DDR5 boards I'm aware of use daisy chain memory topologies which are optimized for 2 DIMM configs at the expense of 4 DIMM configurations due to the difference in trace length between DIMM 1 and DIMM2 in the same channel. On DDR4 this wasn't actually that big a deal since when running 4 DIMMs you would hit the limits of the memory controller in dual rank before you would hit the limits of the daisy chain (at least on the more mature topologies). 4 DIMM configs require much more complicated training algorithms in order to get them to work, and basically only ASUS has managed to get the second 2 DIMM slots to not suck on their ROG boards (on those boards you do hit the limits of the memory controller in dual rank before you hit the limits of the memory topology, roughly 6200MT/s with a good CPU). 

 

Still, there's not really any advantages of 4 DIMM configs over 2 DIMM configs on DDR5 especially, at best it's the same and at worst it's a nightmare. On most boards, those 2 extra DIMM slots should just not be there, especially since the extra ~500MHz you get with a 2 DIMM boards like the Unify-X (tops out at around 7000MHz with a good CPU at ambient, will do over 10,000MT/s if pushed to the limits) compared to a 4 DIMM board like the Unify (tops out at around 6400MHz with single rank DIMMs) will make a much bigger difference than the advantages of dual rank vs. single rank.

[Guest]

Less sticks always = higher frequency. And that's where performance is at. High frequency.

 

A single stick will generally OC better than 2 and 2 better than 4.

 

So yes, 4xw/e is harder to run.

 

Top Memory OC boards such as the Asus Apex will feature only but 2 Dimm slots. Designed for performance and high frequency.

 

Amount per Dimm matters. 2x8gb is easier to OC than 2x16gb even if both are single ranked dimms.

 

Amount posted and available to windows::

In the past (and present) we restrict the amount of available memory in windows to reach top OCs. DDR4 6000mhz, but not with all 16gb available. Less common talked about tricks.... but that's what you use Apex and 5000mhz XMP memory for. Competitive benchmarking figures. But still be running a 4800mhz daily clock after a 6000mhz OC (ddr4).

 

So, just buy how much you need to cover your computing. I recently moved to DDR5 and to keep costs down, I got a 2x8gb kit of ddr5. I have been able to reach 6400mhz from 5200mhz with it.

 

Is more always better? No. Not from a performance stand point. Dual rank can't beat single rank because dual rank just can't run as high of a frequency.