What Is Computer RAM?

As a computer enthusiast, I often find myself building systems for friends or taking apart broken computer for parts or repairs. The one component of a computer that I always tend to have a lot of sitting around and spare is RAM. Lately, I’ve been wondering exactly what it is, so I decided to do some extra research, and I wanted to share that with you.

So what is computer RAM? Random Access Memory, or RAM is a volatile piece of physical hardware that temporarily stores data to be quickly accessed by your computer’s processor. This is called “working” memory and a larger amount of RAM has a noticeable impact on a system’s performance.

There’s so much more to random access memory however, than just a small statement. We’ll need to take a more detailed look!


Important Terms to Know About RAM

Before we get too into detail about RAM though, it’s important to take some time to learn a few key terms. Some terminology you may not use in every conversation about RAM, but it’s important to know them all the same. Especially if you’re planning to buy a new set of memory sticks, as there might be some things that come up you need to know!

  • RAM – Short for Random Access Memory. RAM is where data for your computer is stored temporarily. Your CPU grabs information from the RAM as it’s the fastest version of memory storage in your computer. However, when your computer is turned off, all data in the RAM is wiped clean.
  • Clock – Refers to a specific timing wire inside the central processing unit (CPU). This wire turns on an off at a set speed in order to keep the timing of the CPU in sync. RAM sends and retrieves data each cycle of the clock.
  • SDRAM – Short for Synchronous Dynamic Random Access Memory. This is an older type of RAM that sends and retrieves data only once per cycle of the CPU clock.
  • DDR – Short for Double Data Rate. This is the standard type of RAM that sends and retrieves data twice per cycle of the CPU clock. DDR comes if four generations DDR1 all the way up to the modern DDR4.
  • MT/s – Short for Megatransfers per second. This is how RAM speed is measured. The higher the MT/s, the faster the RAM. Faster RAM also generally runs hotter as a consequence.
  • Voltage – This is a measure of the power consumption RAM uses. Each newer generation of DDR generally decreases the voltage required to operate and is more efficient as a result.
  • DIMM – Short for Dual In-Line Memory Module. These are the rows of pins along the bottom of the RAM stick that is inserted into the motherboard DIMM Slot. Modern RAM has two sets of pins, which is why it’s called “dual in-line”.
  • DIMM Slots – Short for Dual In-Line Memory Module Slots. This is a set of two, four, or eight slots on your motherboard where you fit RAM.
  • Dual Channel – This refers to the DIMM slots on the motherboard. If you have more than 2 DIMM slots, the slots will be paired off in groups of two. Using RAM sticks in these pairs of DIMM slots allows dual channel to increase RAM performance.
  • ECC – Short for Error Correcting Code. This is a RAM feature that detects if data is correctly processed inside the RAM module. If any error is detected, ECC will fix the issue.

A few of these words are more in detail than others and you won’t see them very often. However, if you’re planning to purchase RAM, knowing some of these will pay off if the information is given to you on the product page.


A Closer Look at RAM

The only type of RAM used today is called DDR (Double Data Rate) which began development in 1996 and was debuted in 1997. Before DDR, RAM only sent information to the CPU once per clock cycle (a wire that cycles on and off within the CPU to keep everything in sync) and while there were some breakthroughs to dramatically increase the speed at which RAM operated on this once per cycle system, double data rate technology blew all those advancements out of the water.

DDR sends data twice per clock cycle on the CPU, and no matter how fast a single stick of RAM is, it will always be outpaced by DDR technology. As a result, everything but double data rate has fallen by the wayside and for the immediate future, this looks like it will continue to be the state of things.

DDR itself has had improvements made to it over the years since its initial release. Each new major advancement has been denoted with a number to mark its generation. DDR2 was released in 2003, DDR3, was released in 2007, and DDR4 is the newest generation and came out in 2014.

The main differences in each generation of DDR RAM is the speed of the RAM itself. Each generation has almost doubled in speed since the original DDR. The exception being DDR3 and DDR4. DDR4 has not shown to be a direct increase in performance over DDR3 in a lot of situations. However, being that it’s a new technology, this is sure to improve in the coming years.

Note: RAM is not a user serviceable component in your computer. It’s not advised to attempt any repairs to RAM sticks yourself. Please allow a professional to do maintenance or repairs on your RAM if there is an issue.

RAM speed is generally measured in MT/s or Megatransfers per second, and sometimes this will be labeled as a sticker on the RAM stick itself as “PC” with a number next to it. On a DDR4 RAM stick, for example, you would see this as “PC4” while “PC3” would designate a DDR3 stick of memory. Following this label, you’ll typically see a very large number. This large number is the actual MT/s or speed of the stick. In almost all cases, the faster your RAM, the better it is!

The voltage of a stick of RAM is how much power it consumes. Each generation of DDR has lowered the voltage requirement for RAM and as a result, increased the power efficiency of them as well. DDR3, for example, runs at an average 1.5 volts while DDR4 averages 1.2 volts.

These are averages because there are manufacturers or brands of RAM that might offer a lower voltage requirement at a slower speed, or a higher speed at the cost of more power consumption. Generally these extremes are more suited to very specific computer systems and it’s best to stick with the average voltage requirement for each generation of DDR.

For as long as RAM has been a component in computers, they’ve always been housed on the motherboard itself. The bottom row of a RAM stick is composed of a set row of pins called DIMMs (Dual In-line Memory Modules). These DIMMs would be inserted in a DIMM slot on the motherboard and once the system was turned on, the motherboard would allow the RAM and CPU to communicate.

While these general concept has not changed over the decades, DDR has brought with it the advancement of dual channel technology. Dual channel are pairs of DIMM slots on motherboards that operate in unison with each other and when RAM sticks are placed in these pairs of slots, dual channel increases the performance of each stick.

Dual channel configuration changes from motherboard to motherboard, and so it’s always best to check the manual to see how it operates. If you’d like to go into more detail about motherboards, I’ve written an article about them here.

DDR has, however, created a side effect with motherboards where only one generation of DDR is supported on any one motherboard. In short, if your motherboard supports DDR3 RAM, for example, no other generation of DDR RAM can be used on that motherboard.

This is because of the fact that every generation of DDR has increased the DIMM pin count. As a result, no generation of DDR memory is compatible with another generation.

What Does RAM Do

If you were to think of a computer like a human body, the central processing unit (CPU) would be the brain and RAM would be the short term memory portion of the brain. The entire purpose of random access memory is to quickly give data to the CPU whenever the computer is asked to carry out a task. (If you’d like to go into more detail about CPUs, I’ve written an article about them here.)

Without RAM, computers would be incredibly sluggish. It operates around 100x faster than any hard drive, solid state or hard disk in nature. The unfortunate side effect of being so incredibly fast, however, is RAM also has about 100x less storage space than any hard drive.

RAM is also considered volatile memory, meaning that it requires constant power to retain data within the memory chips. When the system is turned off, all that data is wiped away and allows for a clean slate for the next session.

Like all computer components, RAM stores data in binary code or jumbles of 1s and 0s. It uses this binary code to create addresses of data in a set order. However, if the CPU needs to, it can access specific data addresses randomly from the memory chips. This is where the “random access” in random access memory gets its name. It allows for the computer to be much more dynamic and flexible with how it handles tasks, and it’s why you can open and close lots of applications at once!

Common Misconceptions About RAM

No matter if you’re a brand new computer user, or a veteran system builder, there are certainly some misunderstandings about RAM that have been around as long as the technology itself has existed. Most are potentially harmless misconceptions, but I hope to try and set the record straight on some of this to help make things clearer:

How much RAM is needed? – This is a question that gets asked all the time and you’ll get a lot of answers from different people. Manufacturers will happily tell you that more is better, because they make money off you buying their RAM!

The truth is, the amount of RAM you need is exactly how much RAM your computer uses without running out of memory. This depends entirely on what you use your computer for. Here’s some examples:

  • Do you just use your computer for light internet browsing, email, or listening to music? You don’t need much RAM for this. 2-4 Gigabytes of RAM will be perfectly fine here.
  • Do you use your computer for high end gaming? This typically takes a moderate amount of RAM to do properly. 8 Gigabytes is okay, but I would recommend 16 Gigabytes to be safe.
  • Do you use your computer for a lot of video editing? This is a highly demanding task for a computer to carry out. I would say 16 Gigabytes is a bare minimum and I would recommend using up to 32 Gigabytes.


Can you use different sticks of RAM with different speeds in the same computer? – There are some people that might consider this a computer sin, but in reality, it’s not that big of a deal. If you put two or more sticks of memory into your computer that run at different speeds, the motherboard will simply match them all to the slowest stick of RAM you put in.

If you’re doing high end gaming or video editing, you probably shouldn’t do this though, as you’ll always want your RAM to be operating at its fastest potential speed for these two hobbies. In general though, it’s harmless to the computer itself.


Can you mix and match different brands of memory sticks? – Another topic that some system building enthusiasts might consider blasphemous. In truth though, manufacturers all produce RAM to specific industry standards and you’re more than able to mix and match different brands of memory in your computer. It won’t look as good as all of them being the same, but they’ll work just fine.

The only thing you cannot mix and match is different generations of DDR memory. As mentioned before, a motherboard will only support one generation of DDR, meaning you cannot put a stick of DDR3 and DDR4 together.


Are large heat sinks the way to go for RAM? – This is a very easy to answer question. No, they’re most definitely not. In all honesty, there are some manufacturers that try to sell you RAM with huge heat sinks on them, claiming it improves performance. In truth, RAM operates at a perfectly reasonable heat level without anything fancy attached to it.

The only time you’d want to consider larger heat sinks on your RAM is if you intend to overclock your computer, which isn’t something a new user should be looking to do without a lot of extra research.

Accessing the Data (Conclusion)

RAM is typically a very small component in your computer, and as a result, often very overlooked and taken for granted. Even though the task of random access memory is simple on the surface, how it operates is actually a fascinatingly complex subject. Hopefully I’ve helped shed some light on just what computer RAM is and what it does.

If you have any questions or comments, please feel free to leave them below and I will do my best to respond to them directly!

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