What is DDR4? DDR4 is the next step in the evolution of PC RAM memory, but do you know what it brings to the table?
Last Updated On: August 10, 2015
DDR4 memory is the latest generation of high speed computer memory. The primary advantage of DDR4 memory over DDR3 memory is that it operates at a lower voltage but is capable of faster data transfers. This leads to higher performance with both speed and battery life. However, like with most technology, early adoption comes at a price in regards to both finances and performance.
A bunch of technical details about how this all works is fine, but the primary unspoken question here is, “Is it worth it?” While I certainly can’t answer to the financial aspects of that question, I can certainly help you to understand the pros and cons of the DDR4 memory. Finally, I can help you learn a bit more about the primary players in this market and their contributions to the DDR4 memory development and release.
For this article, we are going to start with a discussion of how computer memory works, how much memory your computer needs, what memory clock speeds mean, performance of DDR4 memory versus DDR3 memory, and whether or not users should upgrade their computers to take advantage of the new memory, motherboard, and processor platform. We also discuss benchmark performance between these two memory types and look at the results.
However, talking about performance, design specifications, and operating variances can leave some people scratching their heads. Like discussing cars, a discussion of computers needs to be based on an equal understanding of how computers operate. Since we are discussing memory in this article, it seems fitting to start with a brief explanation of how memory works. So without further ado, let’s jump into a brief discussion of how memory works.
How does computer memory work?
Here comes the technical part of this article. Just bear with me, I promise this will be quick. It’s important to understand how computer memory works so that when we compare clock speeds, latencies and bus speeds we can conceptualize just how it all fits together in the larger context of a computer system.
Before we continue on with a discussion of the specifics of DDR4 memory, we need to go over a few basic details about how memory works in a computer. When you load a program such as Microsoft Word, Adobe Photoshop, or a game, the instructions that tell the computer what to do are loaded into memory. Since accessing memory is faster than accessing a hard drive, this allows the computer to spend a few minute loading the program and then the program can respond nearly instantly to the commands you give it.
When your memory starts to fill up, the computer starts to take longer to respond as it has to move data from memory to a swap file on the hard drive. For example, if you have 5 copies of Microsoft Word running, and one copy has been idle for the last several minutes, the data for that copy will be written to a special file on the hard drive. When you do switch to that copy, the data is loaded back into memory. This is referred to as swapping, and the file is referred to as the swap file.
How much do I need?
Judging from that explanation, most people come to the conclusion that they should get as much memory as their budgets will allow. While that is certainly one approach, a more efficient solution would be to get enough memory to allow you to run your normal workload of programs without having to access the swap file. Once you figure out what that is, I would add 20% in order to future proof your setup for several years.
Remember though, you just can’t count up the megabytes listed under each software’s system requirements. This is because of two reasons. First, those are the minimum amounts needed. Programs will often times use much more memory than what it says on the box. Second, your operations system (Windows, Linux, etc…) will also use up memory when it loads during the boot-up process. The best way to calculate your memory usage is to setup performance monitoring tools to measure your memory usage and average it over a week or a month.
When it comes to memory in your computer, generally speaking, more is better, but you can indeed have too much of a good thing. The primary performance boost from adding more memory comes from eliminating the need to rely on the swap file as much. Since hard drives are slower than memory, this increases the speed of the computer.
If you have ever used a PC with Windows XP or earlier on it from the late 90s, you might have experienced memory swapping. Consider this scenario. You launch a large program like Adobe Photoshop while having Microsoft Outlook, Internet Explorer, and Microsoft Word open already. After you double-click the shortcut for Adobe Photoshop, you hear the hard drive make a thrashing or grinding sound for 30-45 seconds. This occurs because the computer needs to swap out a large portion of the 256 MB or 512 MB of memory that was installed to make room for Adobe Photoshop.
Fast forward to today. Computers now come with multiple gigabytes of memory, solid state hard drives, and a Windows feature that tries to predict and preload programs you use the most. Hard drive thrashing is a thing of the past. This means also that the old rule of thumb, install as much memory as you can, isn’t really all that valid anymore.
In fact, today, it is really common to run into a situation of diminishing returns when adding memory. Swapping memory to a solid state drive is still slower than storing all the data in memory, so the best guidelines is to install enough memory in order to avoid swapping data to the hard drive. Additional memory beyond that point simply allows for more things to run and preload at the same time, so the marginal benefit of additional memory decreases.
This YouTube video shows you how to use the resource monitor to determine how much memory you are consuming. The best way to size your computer is run this during your normal usage, and note the maximum memory usage. I would then increase that by 20% to provide extra headroom for application upgrades that increase memory usage.
Understanding Clock Speeds
Memory clock speeds are measured in MHz and dictate how often the memory communicates with the processor. In DDR4 memory, the DDR stands for double-data rate and means that the memory communicates with the CPU twice per cycle. Now, the CPU needs to have a matching clock speed on the front size bus. If the bus speed on the CPU is slower than the clock speed, then the processor will be introducing a bottle neck in performance.
Let’s take a look at an example. In this case, let’s look at Crucial Desktop Memory, 16 GB Kit (http://www.amazon.com/Crucial-PC4-17000-Unbuffered-288-Pin-CT2K8G4DFD8213/dp/B00MMLUYQK/). This memory has a clock speed, or data rate, of 2,133 MHz and is DDR4. This means that every second, 17,000 bytes of memory can move in or out of the memory chip.
DDR4 memory has advertised clock speeds ranging from 2,133 MHz to 2,666 MHz. While manufactures advertise these as clock speeds, they are actually data rates and already account for the 2 communications per second of DDR memory. The actual clock speeds are 1,066.5 MHz to 1,333 MHz.
At this point in time, most of the Intel DDR4 processors only support the DDR4-2133 memory. Processors supporting higher speeds are not as common yet. Most processors only support a front-side bus speed of 800 MHz, which allows the PC to support a 1,066 MHz clock speed of memory with a 5/4 bus ratio.
Overall, clock speed does not make a large impact on memory performance. It becomes a factor in performance when you start overclocking your hardware, or making it run faster than the advertised clock speed by increasing the amount of electricity running through it. For a stock system with no overclocking, memory speed does not make a large difference in performance. When overclocking, faster memory can take advantage of the increased speed by increasing the memory bandwidth or the amount of data that can move into and out of the memory every cycle.
Performance vs. DDR3 Memory
As with most technology products, the DDR4 release comes with a hefty premium of around 60% over comparable DDR3 modules. If I were one for bad puns, I’d say that early adopters have DIMM financial future, but I fear I would have to RAM that one down your throats. However, the financial premium isn’t the only premium that early adopters have to pay. Most DDR4 kits that are available at the DDR4 release have a higher latency rating than the DDR3 counterparts. This increased latency rating theoretically translates to lower performance, but until benchmark data is available this could simply be another specification that consumers can safely ignore. Time will tell in that regards.
DDR4 memory has a much higher transfer speed, which means that programs load into memory faster and swap back into memory faster. Another advantage that DDR4 memory modules possess is the higher density of storage. A single stick of DDR4 memory can contain up to 16GB of data, while a single stick of DD3 memory is limited to 8GB of data.
We also see that DDR4 uses a lower voltage than DDR3, which means that battery life is increased in mobile devices such as laptops. Available storage and transfer rates are also higher on DDR4 memory which means that more data can be stored on a single module and it can be read and written much faster.
The CRC feature of DDR4 also ensures that data is written properly to memory without corruption. This is important because it means that applications will experience fewer crashes due to memory corruption. If the DDR4 memory controller detects a write error, it will re-write the data to correct the error automatically.
Should you upgrade?
Finally, we get to the nagging question of whether or not to upgrade a current system to the new memory spec. As we saw earlier, DDR4 memory is only supported on DDR4 motherboards, and those boards only support the Intel Core i7 processor. If you don’t currently have the right Intel Core i7 processor, you will need to replace it, the motherboard and the memory. At this point, you are essentially buying a whole new computer.
A quick search on Amazon.com for ddr4 motherboards indicate that prices range from $250 to over $500 for a motherboard. The Asus Rampage V Extreme motherboard (http://www.amazon.com/RAMPAGE-EXTREME-Extended-Motherboard-2011-V3/dp/B00N1QKUQO/), for example, is $463.99 on Amazon.com and uses the LGA 2011 socket for its CPU. This motherboard requires at least an Intel Core i7 CPU so if your processor is a few years old, you will likely need a new CPU ranging from $320 to $375 on Amazon.com.
Finally, a 16 GB DDR4 memory kit consisting of two 8GB modules runs around $259.99 if you order the Crucial brand kit. This leaves a total expense of $1,098.98 for a bare minimum DDR4 upgrade. Obviously upgrading an older computer is a fairly costly project at this point, and if you do upgrade an older computer you need to be cautious about introducing bottlenecks at the video card or hard drive level. However, as with all things technology, prices should drop as adoption rate increases.
Building a new PC on the other hand is not a completely unreasonable endeavor at that price. Once you get the motherboard, memory, and CPU, you basically have a complete system. You just need to add a case, power supply, hard drive, and optionally, video card and optical drive. If you are in the market for a new PC, try your hand at building your own DDR4 based system. With the performance of the DDR4 platform, the PC you build today should last for an easy five years or more with minor upgrades needed along the way.
If your current workstation is meeting your needs, then upgrading just for the increased performance of DDR4 will not add that much benefit to your current setup. In this case, you might be better off increasing the amount of DDR3 memory you have in your computer, or overclocking your computer.
The main thing to remember is that unless your computer is currently so starved for memory that it runs like a first generation Windows XP computer, you might not notice a large performance increase from using DDR4 memory over DDR3 memory. This is especially true for casual users who just surf the web, read emails, and post pictures of their cats on Facebook. If this use case fits how you use a computer, I would learn more about benchmarking and use a benchmarking tool to compare performance between the old setup and the new setup. On the other hand, if you are a gamer or power user, then the performance increase should be really clear.
If you were already planning on a CPU upgrade, then changing out the memory and motherboard will not take all that much more effort. In this case, I would say to go ahead and make the change. If you are on the fence about upgrading, then I say to take the plunge and do it.
Wrapping it all up
In this article, we took a long trip down the rabbit hole of DDR4 memory. We looked at how much memory is needed, and a methodology for measuring your memory usage. We then took a look at clock speeds of DDR4 memory and what it meant for the end user. We looked at the performance of DDR4 memory versus DDR3 memory, and then we moved into a discussion of upgrading a computer to DDR4 memory.
We also worked through an upgrade scenario where we took an older computer and changed out the motherboard, processor, and memory. This scenario had a sticker price of around $1,098 before shipping and taxes were figured in, which is close to the cost of a really nice computer built on the DDR3 platform. Lastly, we ended with a discussion of when it makes sense to upgrade and when it makes sense to wait.
During a computer upgrade, it is imperative to set reasonable expectations. The performance benchmarks for DDR4 memory versus DDR3 memory do not indicate a large jump in performance so expecting to take a recent computer, one built or purchased within the last year, and upgrade it to the DDR4 to get lightning fast computing is not a realistic expectation. In fact, the benchmark data suggests that in two computers of equal specifications, one running DDR3 and one running DDR4, performance will be very similar in a variety of practical applications.
Finally, we even got a bit technical in discussing how computer memory works. When evaluating different memory products it helps to be able to conceptualize how each component works, and what the effect is on the larger picture of computer performance.