It's daft to run anything less than 3200mhz RAM with Ryzen processors, as the RAM speed determines the Infinity Fabric speed, and the difference between 2600 and 3200 is statistically significant. There is also very little reason to purchase specialty dual rank RAM even with Intel, much less AMD, and you would be well advised to spend slightly more on G.Skill Flare DDR4-3200 and run them at rated speed and timings.
This Thread [Ryzen RAM] Dual Ranked 2666 oder Single Ranked 3000? | ComputerBase Forum : claims
'Laut den Tests der PCGH (Print) liegt die Performance von 2666 DR in etwa zwischen 3000 und 3200 SR.',
translation: 'according to PCGH magazine 2666 dual rank equals 3000-3200 single rank'.
Similar results are to be found here RAM-Overclocking getestet: Ryzen profitiert von DDR4-3200 und Dual Rank - Golem.de
Dual rank RAM at less Mhz is cheaper than required higher speed single rank RAM for same performance,
and you sugggested overclocking, voiding warranty.
Questions not answered.
ryzen9000, I read only English, so I can not discuss your referenced documents. Rank seems to be a confusing parameter with respect to memory. In my understanding, a dual rank memory stick (usually double sided) means two chip loads on the memory bus which slows down the bus. When two single rank sticks are plugged into the same channel in the MB, then there is also two chip loads on the memory bus, thus slowing the bus. When two dual rank sticks are plugged into two slots on the same channel then there are four loads on the bus slowing it down even more. The two loads consist of a selected chip and a non-selected chip. Obviously only the selected one will give or take data but the other presents capacitance and leakage to the bus even though it is not selected. Either I am totally wrong or others need to do some studying on memory rank. In my case (1950X, quad channel) I have the maximum memory capacity (32 GB) possible in single rank consisting of a quad channel memory kit of SINGLE rank sticks (4). I avoid dual rank memory if I can get the memory capacity I want without using dual rank arrangement. I should point out that you are not speaking to AMD here in most cases and certainly not I because I do not work for AMD. To contact AMD please open an AMD Online Support Ticket. Settings in the UEFI and AGESA do affect memory speed capability. At the very beginning of Ryzen, it was very sensitive to memory and memory settings. Things have got somewhat better. Usually it is the Main Board vendor that specifies the maximum memory speed supported, but still a good idea to ask AMD. Enjoy, John.
Overclocking is when you run a piece of hardware outside of specifications, whereas running DDR4-3200 at 3200mhz is...running hardware at its rated specs. Here is a good article for you to read, showing that at equal timings, single rank chips are faster and lower latency. So I stand by my original statement, don't get those chips, get some G.Skill Flare DDR4-3200.
Zion, from your own suggested article, on first page, it reads
"Officially, AMD Ryzen platforms support the following memory configurations:
- Dual-Rank w/ 4 DIMM: Up to 1866 MHz
- Dual-Rank w/ 2 DIMM: Up to 2400 MHz
- Single-Rank w/ 4 DIMM: Up to 2133 MHz
- Single-Rank w/ 2 DIMM: Up to 2667 MHz"
This means that, while the RAM surely will cope, and as well the memory configuration bar might have been raised one tad meanwhile (dual rank 2666 Mhz)
but not been announced properly for whatever entangled reasons, still anything above 2666 Mhz overclocks related parts of the CPU. Right?
On further detail, the test reported in that article is plain memory writes and reads. It fails to display the relevant accessing advantage
dual rank has, as pointed out by MisterJ, and the benchmarks in the two articles i posted.
I'll think about an AMD Online Support Ticket.
ryzen9000, "...relevant accessing advantage dual rank has, as pointed out by MisterJ...". The only advantage (I am aware of) to dual or higher rank memory is to be able to have larger memory capacity. As the memory chips get larger, we will see larger capacity sticks that are single rank, right now it seems to be 8GB. My single rank memory described above has an SPD rated speed on 2400 MHz and an XMP 2.0 of 32 MHz. My system runs fine with the XMP 2.0 selected, i.e. memory is running at 3200 MHz. One AGESA update AMD released some time ago had an article on the AMD Gaming Blog and described using the UEFI settings to obtain faster memory speeds. Several other updates of AGESA and UEFI code have improved memory performance in Ryzen. Please be sure to ask AMD about their poor communication. Checking the Gaming Blog regular may be what AMD recommends. Have fun and enjoy, John.
Yes, i misread your post somewhat about dual rank two chips. Fact seems to be, according to fps and other benchmarks i pointed out earlier,
that two chips on DIMM alias dual rank RAM, grants interleaved access advantage resulting in 7-10% speed advantage compared to single rank
clocked at same Mhz.
For VRM construction reasons, currently i opt for an B450 MSI board. AGESA changes haven't been adopted fully by MSI, they stay with quite 'conservative' AGESA code 1004c currently, so some latest tinkering speed records don't apply for MSI boards probably. Unfortunately, there don't seem to be properly done
Ryzen-AM4-boards by any company in mainstream, thus there's no best choice available. In case anyone wanted to point some AGESA 1006+-adopter.
You're right about poor communication/information on part of AMD, maybe they believe everyone is computer nerd figuring things out anyway.
Reply from AMD support linked to https://www.amd.com/de/products/cpu/amd-ryzen-5-2600 , stating
2933MHz, not mentioning ranks, but apparently for one pair of DIMMs single rank.
Question on dual rank Mhz pending.
ryzen9000, not sure what this means: "...that two chips on DIMM alias dual rank RAM, grants interleaved access advantage resulting in 7-10% speed advantage compared to single rank...", but as I understand it there is not interleaving due to dual rank. For me this statement makes no sense. I guess since we are not going to agree, then you should do some testing with single and dual rank memory and come to you own conclusion. Good luck and enjoy, John.
rough translation of last reply from AMD:
"...Ryzen 5 2600 supports DDR4 memory at dual channel up to 2933MHz.
We have no additional information about differences between single- and dual-rank regarding RAM performance and longevity [longevity data I did not ask for].
You should take care the RAM you use is listed in the Qualified Vendors List of the motherboard manufacturer."
A “rank” is a group of memory chips that receive read and write commands as a group. Some memory sticks have all of their memory chips in one group, and those are single rank (SR) DIMMs. Other memory sticks split their memory chips into two groups, and those are called dual rank (DR) DIMMs.
DR modules can often be a smidge faster thanks to a capability called “rank interleaving,” wherein the second memory rank can still perform work while the first is being refreshed for use. However, DR modules are often harder for a system to drive to high frequency, which is why most high-performance memory kits use multiple 4GB or 8GB SR memory sticks. The extra frequency achievable by the SR memory modules is often enough to overcome the small performance benefit of DR DIMMs, too.
You can often tell single and dual rank memory apart by looking at the product code, which might say 1Rx4 or 1Rx8 for single rank, or 2Rx4 or 2Rx8 for dual rank. And though you should always verify with spec sheet, it’s a decent shortcut to assume an 8GB DDR4 DIMM is single rank, whereas a 16GB DIMM is almost certainly dual rank.
As we finally come to the data, our results lend credence that—all things being equal—DR memory configurations are a touch faster than SR configs for the purposes of PC gaming. But all things aren’t equal when it comes to overclocking memory, and we’ll explore that in the conclusion."
- Ryzen Pinnacle Ridge memory clocks higher than 2600 Mhz, 2933 Mhz, as quoted above
- the RAM list provided by MSI has just two 3466 Mhz examples, 3466 Mhz Flare X not available anymore, and one 2nd choice Kingston HyperX. Dual rank versions in the list has just rather lame 2400Mhz examples.
- theres G.Skill Flare X series 'made for AMD', whatever that really means, if anything. Expensive. The 3466 Mhz version has vanished from the shops and as well G.Skill website
- theres G.Skill Trident Z RGB 3466 Mhz 'made for AMD' CL18-22-22-42 (F4-3466C18D-16GTZRXB), which is 40 bucks cheaper than 3200 Mhz Flare X currently (2x8Gb), but no RGB-free version made. Could do. In general, RAM currently is a rip-off.
- theres Ryzen DRAM Calculator which may come in handy for people calculating proper (oc) timings
- a rule of thumb for which memory to choose, if provided QV lists don't serve, is nowhere to be seen, except for 'get some samsung chipset DIMM'.