Single Rank vs Dual Rank Memory (RAM) – Whats better for gamers?

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Many minor yet unique RAM specs might result in a significant performance increase. Memory rankings are one such element.

What Is The Meaning Of Memory Ranks?

Every memory chip has a stack of DRAM chips accessible while writing or reading data. This stack is referred to as a “rank” by the independent standards group JEDEC. These memory modules, or ranks, may be positioned on either one or both sides of a memory block.

A 64-bit wide data frame (a collection of memory chips) is a single rank arrangement (72 for ECC memory, which has eight extra bits for error checking). In other terms, it’s a single memory vault or collection of memory chips.

Dual rank chips will contain two of these data packets and be 128 bits large as a result. In layman’s terms, a dual-rank memory DIMM is the same as having two conventional “single-rank” memory modules on the same DIMM. As a result, a dual-rank memory chip should have twice the bandwidth of a single-rank chip.

Discrepancies in Memory Ranks

The degree of rankings might indicate the RAM stick’s storage capacity. However, it is determined mainly by the design of the chips installed on the memory stick and the DDR generation.

Since most IC chips can only accommodate 1 GB of storage, many modern DDR4 16 GB blocks are dual rank. On the other hand, crucial’s greater capacity RevB modules provide up to 16 Gb of space in a single rank (utilized in their Ballistix Max memory chips).

Unlike single 8 GB or even 16 GB modules, dual-rank or quad-rank 32 GB modules are possible. There is currently no DDR4 32 GB single rank memory chip available. However, as technology progresses, we may see more of them.

Advantages of a Single Rank and a Dual Rank

Dual Rank Advantage

Even though a RAM module may contain two or more levels per unit, the memory controller can only address one at a point. The CPU may read one memory bank while the other goes through a refreshing round (the process of becoming ready to be addressed).

This method, known as Rank Interleaving, is analogous to SDRAM Bank Interleaving. Since it minimizes memory response times, masking and pipelining refresh cycles typically improve CPU-intensive applications.

Single Rank Advantage

When the memory controller goes through a lot of ranks instead of just one, there may be a delay that affects some things.

Furthermore, since Single Rank (SR) DIMMs contain half as many chips as Dual Rank (DR) modules, they emit less heat and may be more reliable. This advantage is also why they are a popular option among overclockers.

Benchmarks

Benchmarks contrasting Single and Dual Rank RAM at comparable speeds demonstrate that the latter has a minor advantage (as predicted) – ranging from 3% to 5%.

Igor’s Lab produced comparable findings, however their studies focused exclusively on gaming performance.

In general, dual-rank configurations are 5-10% quicker than single-rank PCs in gaming demands, with the gains being undeniable on AMD’s Ryzen CPUs.

As you would expect, quad-rank memory DIMMs exist, which may be considered two dual-rank DIMMs on a monolithic kernel. Again, since only one of the four ranks is available, these modules are much slower than single-rank DIMMs. As a result, quad-rank modules are not standard in consumer PCs.

Random Benchmarks also did a great video on it:

Difference between Memory Rank and Memory Channel

Ranks are assigned based on the number of memory chips on a RAM stick. This feature is distinct from the number of memory channels supported by a CPU and motherboard system.

Every memory channel enables concurrent access to a memory module, considerably boosting available memory bandwidth. Every band between the RAM and the CPU is 64 bits wide, providing a 128-bit width in a dual-channel setup.

With a dual-channel, dual-rank arrangement, you get the best of both worlds, a higher bandwidth from a dual-channel design, and rank interleaving.

There are two popular methods for setting up a dual-rank, dual-channel setup:

  1. Utilize four DIMM slots in conjunction with four single-rank RAM modules.
  2. Utilize two DIMM slots to accommodate two dual-rank modules.

It is usually preferable to have more channels than dual or quad ranks. Always prioritize a dual-channel configuration first, followed by greater memory bandwidth and lower latency. Only then should the degree of ranks be considered.

Conclusion

The performance differences among the single rank and dual rank memory as assessed by benchmarks may seem tiny, but they add up.

Stacking more channels, improving memory rates and latency, and providing appropriate RAM capacity will result in a considerable increase in overall system performance and responsiveness.

DRAM chips on a DIMM don’t always identify their rank by their physical arrangement. As a general rule, a single-sided DIMM may not necessarily be a single-rank DIMM, and the same is true for a dual-sided DIMM.

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