Single Channel vs Dual Channel Memory: Which One Is Better?
To summarize, I’d say that yes, in the comparison of Single Channel vs Dual Channel Memory, Dual Channel does come out as the winner. That being said, the benchmark and real life results are way different from the differences that were calculated on paper. Theoretically, there should have been a 2x difference, while in reality, the Dual Channel seems to exhibit only a 16-17% advantage at best in overall usage. While attaining a difference of 12-13% is also desirable, it is certainly not worth the hype that surrounds Dual Channel Memory. In most cases, the normal user would not even notice the difference between the two. And as far as power users are concerned, even though Dual Channel does come out on top, they would not be sacrificing anything significant.
SEE ALSO: DDR3 vs DDR4 RAM: Is It Worth The Upgrade?
Real Life Performance
While the above benchmarks proved to be in slight favor of the Dual Channel Memory module, in my real life usage, I found there to be a negligible difference between the two. Pages loaded slightly faster and my software such as iTunes, Google Chrome, and Microsoft Office ran at equivalent speeds. And yes, I made sure to clear the cache before testing each Memory setup to ensure precise results.
Additionally, I also ran some games to test their performances. The results are shown in the graph below.
Gaming Benchmarks – FPS – Higher is better
We tested the Dying Light, Metro Last Light, Grand Theft Auto V, and The Witcher 3: Wild Hunt on our system when paired up with the MSI NVIDIA GTX 1060. The results were more or less the same, with the Dual Channel having a slight advantage over the Single Channel memory modules. That being said, there were cases where the Dual Channel mode experienced performance drops, which was quite evident in the Witcher 3. Even so, the difference between the two is still negligible whatsoever.
What Does Quad, Dual, and Single Channel Even Mean?
Essentially, if you run one stick of RAM in your computer, it will be running in a single channel configuration. If you run two sticks of RAM, they will be running in dual channel configuration. And, if you run four sticks of memory, they could be running in quad channel configuration, depending on whether or not you have a CPU/motherboard combination that supports quad channel memory.
You can run three sticks of memory, but there aren’t a lot of motherboards that use triple channel configurations. So, in most cases, installing three sticks of RAM would be utilizing two of the sticks in dual channel mode and one of the sticks in single channel mode.
The advantages of running two or four lower capacity memory sticks in dual or quad channel configuration (again, not all CPU/motherboards support quad channel memory) is that they will provide the same capacity as a larger single stick of memory, while at the same time doubling and quadrupling the amount of memory bandwidth that is available.
When you add the second (and fourth) stick of RAM, you are adding a parallel channel that can be accessed simultaneously with the first stick of RAM. The common conception is that by doubling or quadrupling the available memory bandwidth, dual and quad channel configurations will make your system perform better.
Is that true, though?
How Memory Works
The RAM in the system is controlled by a circuit that is referred to as Memory Controller. The RAM and the Memory Controller are connected through a series of wires, collectively known as a Memory Bus. Now, these wires are further divided into three groups – Control, Data, and Address. The Control wires are responsible for sending the commands to the memory modules, which contain information about what kind of operation is being performed by the system. The Data wires will carry the data that is either being read from the memory to the memory controller or being written from the memory controller to the memory.
The Memory Controller is also responsible for defining the memory speeds (or clock rates) for the said memory module. For example, if the Memory Controller states that the max clock rate it supports is 1333 MHz, even if you install a 2400 MHz memory module, the system will be able to utilize the potential of just 1333 Mhz only, thus underclocking the RAM. Now that you’ve understood how basically a RAM functions, let’s move on to compare Single Channel vs Dual Channel Memory.
Bandwidth
Bandwidth is the maximum theoretical transfer rate of a communications channel and is measured in megabytes per second (MB/s) or gigabytes per second (GB/s). Current technologies such as DDR (Double Data Rate) can transfer two data bits per clock cycle. As a result, they achieve double the transfer rate compared to traditional memory technologies. For example, the DDR3-1333 MHz module may actually be working at 666.6 MHz, but transferring two data bits per clock cycle. Furthermore, bandwidth also depends upon the width of the data bus. A single channel makes use of a 64-bit device width, which basically means that 64 bits of data are transferred at each transfer cycle. Thus, theoretically, bandwidth can be calculated as:
bandwidth = DDR clock rate x data bus width / 8
So, for a single channel DDR3-1333 Memory, the theoretical bandwidth comes out to be
Bandwidth in Single Channel = 1333 x 64 / 8 = 10,664 MB/s or 10.6 GB/s
Newer technologies such as dual channel technologies focus on doubling the data bus width by increasing the number of data wires available in the memory bus. A dual channel makes use of 128-bit device width, ie, 128 bits of data are transferred at each transfer cycle (as shown in the architectural differences above). This, in turn, impacts the system by theoretically doubling the bandwidth. For example, for a dual channel DDR3-1333 Memory, the theoretical bandwidth on calculation comes out to be
Bandwidth in Dual Channel = 1333 x (64 x 2) / 8 = 21,328 MB/s or 21.3 GB/s
Note While the difference between the bandwidths is staggering, do keep in mind that this is just a theoretical calculation of the two values. Actual performance between Single Channel vs Dual Channel memory may differ, which is discussed further.
Interleaving
Interleaved memory is a design made to compensate for the relatively slow speed of Dynamic Random-Access Memory (DRAM) or core memory. This is done by spreading the memory addresses evenly across memory banks. The memory bank consists of multiple columns and rows of storage units spread across several chips. Each memory module can have two or more memory banks for program and data storage.
Interleaved memory results in contiguous read and writes. This actually uses each memory bank in turn, instead of using the same one repeatedly. Eventually, it results in significantly higher memory throughput as each bank has a minimum waiting time between reads and writes.
Interleaving Memory Read and Write
Using a Dual Channel Memory increases the number of memory banks, thus, in turn, improving the interleaving design to result in better multitasking.
Single Channel vs Dual Channel Memory: What’s Better For You?
As you can see, while the Dual Channel Memory does perform better than the Single Channel Memory modules, the difference between the two is in no way staggering. In the end, it all comes down to the price point. There may exist cases where you might be able to purchase a Dual Channel kit cheaper than the Single Memory module, or vice versa. That being said, purchasing a Single Channel Memory does leave the door open for future Dual Channel Utilizing. The only thing that you have to keep in mind is the fact that your future purchase should be similar, if not identical, to the already existing memory in order to ensure proper functioning.
Finally, your primary focus should be on the RAM capacity and the clock speeds. In the real world usage, these two factors are gonna make the most difference, regardless of whether being used in Single Channel or Dual Channel. Our suggestion would be to finalize on the capacity and the clock speed of your RAM and then simply watch the market for a better deal on either Single or Dual Channel to finalize your purchase.
So that’s all there is to Single Channel vs Dual Channel Memory from our side. Make sure to share with us your thoughts on this, as well as your experiences, in the comments section below.
So, Should I Just Stick to Single Channel Memory Then?
The tests above show that, for gaming, there isn’t any kind of noticeable difference between running your memory in single and dual channel memory configurations.
This, of course, doesn’t mean that dual channel configurations shouldn’t be considered. There are cases where it will make sense to utilize dual channel configurations:
1. You Might Find Dual Kits to Be Less Expensive
In some cases, especially during sales, you may be able to find a dual kit of RAM at a lower cost than a single stick of RAM. Typically, single sticks of RAM are less expensive than dual kits. However, in the world of PC hardware, there are hundreds of sales every day on the various components from the multitudes of brands and manufacturers.
So, if you can grab a dual kit of RAM for less money than a single stick of RAM (all other factors equal), then do it.
Another point to consider, though, is how many slots your motherboard has and how much RAM you can afford right now. If you can only afford 8GB of RAM right now and a motherboard with only two DIMM slots, it might make more sense to go with a single 8GB stick of RAM rather than dual 4GB sticks of RAM.
The reason is that, if you ever wanted to upgrade to 16GB of RAM, all you’d have to do is purchase another 8GB stick of RAM. If you would have chosen dual 4GB sticks of RAM, you’d have to get rid of both of those sticks and buy an entirely new 16GB kit.
2. Dual Channels for Aesthetic Purposes
The other reason to choose a dual or quad kit over a single stick of RAM is for aesthetic purposes. A single stick of RAM on a motherboard with four DIMM slots won’t look as clean as if you were to use two sticks of RAM—or, better yet, four sticks of RAM.
So, if the price difference between a single stick of RAM and a dual kit (or quad kit) of the same capacity is minimal and you are taking the aesthetics of your build into consideration, then you might want to try and fill up your DIMM slots.
3. Dual Channel Beats Single Channel in Professional Applications?
This is a test for another day, but of the benchmarks I’ve seen where single channel memory is stacked up against dual channel memory configurations in professional applications (editing, design, CPU-laden tasks, etc.), there is a bit more of a difference in performance between the channel configurations.
So, if you will be using your computer for any of those kinds of tasks, going with a multi-channel memory configuration might give you a boost in performance.
Single Channel vs Dual Channel Memory: Not That Big of a Difference for Gamers?
We took two kits of DDR4 3200MHz RAM and tested them in pretty much every common memory configuration available. One of the kits was a 4x4GB kit and the other was a 4x8GB kit.
That allowed us to test the following channel configurations:
- 8GB Single Channel and 8GB Dual Channel
- 16GB Dual Channel (w/two sticks) and 16GB Dual Channel (with four sticks)
We benchmarked these different configurations in five different games: Dirt 4, PUBG, Middle Earth: Shadow of War, GTA V, and Battlefront II. Our test system used an i7-8700K, a GTX 1070, and a 1920×1200 monitor.
Our results are below.
*NOTE: In our test, we originally made the error of thinking that we were running our 4x8GB configuration in quad-channel configuration. However, as pointed out by Xenotester in the comment section, the Intel Core i7-8700K does not support quad-channel memory, but, rather, is limited to dual channel configurations. Because of this, the results below do not portray an accurate view of the difference between quad-channel and dual-channel memory performance in gaming. So, when looking at these benchmarks, the only real takeaway comes from A) the single channel vs. dual channel performance, and B) the difference between running four sticks of RAM in dual channel and running two sticks of RAM that equal the same capacity in dual channel.
Test Results & What They Mean
Across all five games, there was no significant difference between how single and dual channel memory performed. Again, we errored in our belief that running four sticks of RAM on a Z370 motherboard would be utilizing a quad channel configuration. So, the 16GB quad vs 16GB dual results shouldn’t mean anything other than that running four sticks of 4GB of RAM in dual channel configuration didn’t really offer any performance boost over running two sticks of 8GB of RAM in dual channel configuration and vice versa.
The only metric that really varied that isn’t shown in this graph, is that on the single channel memory configuration, the CPU usage was anywhere from 10-25% higher than on the dual channel configurations. So, I think what happens is that in dual and quad channel configurations, the extra available memory bus takes a bit of the workload off of the CPU. I could be wrong about that, but at first glance, that seems to be what is happening.
So, you could theorize that with a budget-friendly processor, there is the potential for a noticeable performance drop in single channel versus dual or quad channel configurations, but even then, my guess would be that it would also be minimal.
While I’ll admit that my test methodology wasn’t the strictest and perhaps it would make more sense to run the same tests with a more budget-oriented gaming PC, I think in the grand scheme of things this points to the fact that dual channel configurations don’t offer that significant of a difference over single channel configurations—at least in gaming performance.
Single Channel vs Dual Channel Memory: Architecture
A single stick of RAM operates on a single 64-bit data channel, which means that it can push data down to a single pipe that is 64-bits in total width. The architecture for a Single Channel Memory is shown below.
Single Channel Architecture
That being said, nowadays, modern systems support multi-channel platforms as well. In the case of Dual Channel Memory, the system makes use of not one but two memory channels. Now, we have got 2×64-bit channels available to the memory. This means we’ve doubled the data traces running on the memory bus, and now have an effective 128-bit channel.
Dual Channel Architecture
If you take a closer look at the image above, you’ll see that both the channels support data bit ports from D00 to D63, that is, 64 ports. That being said, effectively, the ports on the channel 2 are taken from D64 to D127, thus emulating the next set of 64 ports. As a result, the system regards the channel width to be a total of 128-bit width rather than 64-bit.
Effective Dual Channel Architecture
As you can see above, the D0-D63 represent the first channel, D64-D127 represent the second channel. Thus, modules can process 64 bits of data at any given time, and so dual-channel platforms will read and write to two modules simultaneously (saturating the 128-bit wide bus).
Benchmarks
While benchmarking is not equivalent to real life performance, it is far more realistic than the theoretical calculation. As such, we compared a Single Channel Corsair Vengeance 8GB DDR3 RAM with a Dual Channel Corsair Vengeance 8GB (4×2 kit) DDR3 RAM, both costing the same $64.99. The following benchmarks were conducted on our test machine.
Euler 3D
Euler 3D RAM CFD Benchmark – Higher is better
In our Euler 3D Benchmarking, the Dual Channel Memory configuration performed approximately 17% better than the Single Channel Memory configuration. The difference between the two puts the Dual Channel Memory ahead of its competitor. This advantage should prove to be useful for users carrying out heavy-duty computation, simulation, and compilations.
MaxxMem – Copy, Read, Write, and Bandwidth
MaxxMem Copy Read Write Bandwidth – Higher is better
Upon our tests with MaxxMem, we tested the memory copy, memory read, memory write, and memory bandwidth performances. These tests are measured in Megabytes per second. As such, we saw significant performance differences between the Single Channel vs Dual Channel Memory modules, with the Dual Channel having a clear lead in each case. That being said, it is worthy to point out that the performance is no way near to the theoretical calculation, considering the bandwidth should have been doubled when instead we observed a ~20% boost on average.
MaxxMem – Memory Latency
MaxxMem Memory Latency – Lower is better
Latency refers to the delay before a transfer of data begins following an instruction for its transfer. In our memory latency test on MaxxMem, we found that there was a mere ~2.7% difference in the latencies, with the Dual Channel memory module still performing slightly better than the Single Channel.
Handbrake Video Transcoding
Handbrake Video Transcoding – Lower is better
On our Handbrake Benchmarking, we saw almost a 4.5% advantage in favor of Dual Channel Memory. That being said, Handbrake in itself is a really powerful tool, that pushes the system to its limits. Even for most heavy-duty users who do video ripping or transcoding, the slight difference wouldn’t make much of a difference.
Adobe Premiere Encoding Pass
For video editing, Adobe Premiere is one of the most demanding software out there. In our benchmarking test, we found that the Dual Channel setup saves approximately 8 seconds in overall rendering time, thus giving it the slight edge. While the difference here is quite insignificant, for systems that render all day long, the rendering time gap could prove to be bigger, thus saving a few crucial minutes off the shelf.
