What is RAM?
Before we break down the various generations of RAM, i.e DDR4 vs DDR3 vs DD2 vs DDR SDRAM, we should probably start with the basics. Firstly, DDR is RAM. If you have a computer, you are already using Computer RAM, whether or not you know or understand what exactly it does. RAM is basically computer data storage for programs currently in use. When you click on a program icon, the program loads onto RAM after which you can use it. Most RAM chips wipe their memory once the computer is powered off. That’s why you always need to load your programs.
What is DDR SDRAM?
The DDR in this write-up is all SDRAM. DDR SDRAM stands for Double Data Rate Synchronous Dynamic Random-Access Memory. Don’t let the big words shake you. The magic in SDRAM is that it synchronizes data transfer between the CPU and memory.
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DDR SDRAM has seen a number of iterations since the year 2000 when the first DDR was released. With the advent of online shopping opening up new markets worldwide, consumers need a passing understanding of these computer specs before purchasing a device. DDR3 was the most popular SDRAM on the market before the release of DDR4. Since 2014, however, the current crop of computers come with DD4. This is only natural, given that each iteration of DDR comes with incremental performance improvements over the older generation.
Keep this in mind though; 4 GB of DDR2 is very different from 4 GB of DDR3. For one, it’s not interchangeable. You will need to either buy RAM appropriate for your computer or to replace the motherboard altogether. To clearly map out the differences in SDRAM, please have a look at this:
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DDR4 vs DDR3 vs DDR2 vs DDR
|SDRAM version||Release Date||Bus Clock|
DDR SDRAM has incrementally improved upon the performance and battery consumption over the years. The SDRAM chips initially started out with between 2.5~2.6 volts way back in 2000 for DDR. At the time, this was a breakthrough that took more than a decade of elbow grease. Currently, that figure is further down to as low as 1.05~1.2 volts in DDR4. While this might still not sound like much, it does its part helping computers to emit less heat, improve overall battery efficiency and power economy. For systems with a bunch of RAM chips, the effect is obvious when consumers get the power bill at the end of the month. More so, they spend less on cooling systems.
The addition of SDRAM into the equation saw an improvement in data transfer between CPU and memory. A CPU using SDRAM can process data even as it queues up other processes. More on that point, in a battle of DDR4 vs DDR3 vs DD2 vs DDR, the clear winner is DDR4, the newer, more powerful iteration which improves upon advancements by it’s predecessors.
DDR4 and DDR3 both have 8n prefetch architecture. These transfer 8 bits of data per cycle from the memory array to the memory internal I/O buffer in DDR4 and DDR3. In an 8n prefetch architecture, the internal I/O buffer will operate 8 times faster than the memory core. DDR2 comes with 4n prefetch to DDR’s 2n architecture. This number is 4 bits of data in DDR2 and 2 bits of data per clock cycle in the case of DDR SDRAM.
DDR5: The Holy Grail
JEDEC, the 300 member-strong semiconductor engineering standardization body gave us a strip-tease on what to expect in the next generation DDR5 SD RAM. As expected, JEDEC is vague about the details at this stage. But firstly, expect a further reduction in power consumption compared to DDR4. What’s more DDR5 will double the memory bandwidth and capacity of DDR4, for starters. It’s also rumoured to be much cheaper than its predecessors. Unfortunately, we will have to wait till 2020 onwards for it to make it to regular computers.
Not having enough RAM in your PC can truly wreck your day no matter what you're trying to accomplish. If you're in the market for more RAM, you might be wondering about the differences between DDR3 and DDR4 RAM, and whether or not they really matter to you.
The random-access memory (RAM) in your computer is used to hold data that is frequently accessed by your processor (CPU). It can be likened to your office where you have a corkboard with a bunch of papers on it for easy, quick reference.
Why use RAM when we have hard-disk drives (HDD) and solid-state drives (SSD)? Reading from and writing to a hard drive, even a solid-state drive, is much slower than reading from and writing to RAM. The connection between the CPU and the RAM, also know as the memory bus, is designed for speed, and the entire package uses a small amount of energy to do its job. Accessing a hard drive is sort of like standing up, opening a filing cabinet, and pulling out a paper — much slower than if the paper is already on a corkboard in front of you.
DDR3 and DDR4 RAM don't work together
The first noticeable difference between the two RAM-types is the physical layout of the pins on each module. DDR3 RAM uses a 240-pin connector, while DDR4 RAM uses a 288-pin connector.
Why are they different? A motherboard and CPU that work with DDR3 RAM don't work with DDR4 RAM and vice versa. The different connectors ensure no one accidentally installs the wrong type of memory. Also, take note that not all RAM works with all processors, even if it fits into the motherboard. Take time to research and make sure all parts of your PC are compatible. If you need a hand, PC Part Picker has a wonderful tool that shows you what works together and what doesn't.
You might also hear mention of DDR3L RAM. This RAM has the same pins and works with any CPU and motherboard that works with DDR3 RAM. The difference? DDR3L RAM can function at both 1.5V and 1.35V, while DDR3 RAM is stuck at 1.5V.
DDR4 RAM looks faster on paper
When studying data transfer rates of RAM, you'll see it measured in either million transfers per second (MT/s) or gigatransfers (billion) per second (GT/s). A higher transfer rate means you have more bandwidth and will thus be able to transfer more data at once. DDR4 RAM can transfer data at a rate between 2133MT/s and 4266MT/s, while DDR3 RAM can only hit transfer data rates between 800MT/s and 2133MT/s.
Another number you'll see is the clock speed, which is how fast the RAM can read and write data. The clock speed number, represented in megahertz, is the number of cycles per second the RAM can perform.
Finally, Column Access Strobe latency, also known as CL, must be taken into consideration. CL is the number of clock cycles it takes for the RAM to deliver a piece of data requested by the CPU. Even if you have blazing fast clock speeds, high latency will put a damper on your RAM party.
If we compare four types of Corsair RAM, it's evident that a higher clock speed and the higher transfer rate afforded by DDR4 RAM doesn't necessarily always make it better.
When shopping for RAM, always take all specifications into consideration. Higher numbers on the label don't necessarily mean faster performance.
DDR4 RAM uses a lower voltage
The standard voltage of DDR3 RAM sits at 1.5V, while DDR3L RAM can use both 1.35V and 1.5V. DDR4 RAM, on the other hand, uses 1.2V. While this isn't a big difference for most of us using one or two RAM modules — you're not going to see a difference on your electricity bill — server farms with thousands of RAM modules will definitely enjoy sucking less power.
DDR4 RAM costs more
When DDR4 was first released, the price gap was quite large. The gap has shrunk a lot since then, but in general, DDR4 RAM still costs more.
If we look at the prices of the Corsair Dominator Platinum RAM from the table above, it's clear that even though the DDR3 RAM performs better when considering clock speed versus latency, it is still cheaper — DDR3 costs about $115, while DDR4 costs about $130. Again, this isn't a huge difference if you're only buying one or two modules, but in instances where you need a lot of RAM, the cost can really add up.
So...which RAM do I choose?
Going with DDR3 or DDR4 RAM really depends on what other hardware you're currently using, and what hardware you plan on using in the future.
If you have an aging motherboard and a 4th- or 5th-generation Intel CPU, you'll probably be going the route of DDR3 once you figure out all the compatibility stuff. If you have a recent motherboard and, say, a 6th-generation Intel CPU, DDR4 RAM is a good investment for the future — it's hard to believe DDR4 RAM won't be used for quite some time to come.
Which RAM do you use?
What are you running in your PC build? Were you able to go with DDR4, or are you still using DDR3? Tell us in the comments section below!