Random Access Memory

But what is RAM? In a nutshell, it’s an extremely fast type of computer memory which temporarily stores all the information your computer needs right now and in the near future. It’s where your computer loads up all the things it thinks it will need to find out soon, so that when it does need something, it can read it super fast. It’s quite different from your system’s storage, like its hard drive, where information is stored long term.

If this is all semantics (words) to you and you just need to know how to install some RAM, or want to find out how much RAM you need, there are guides for that, too.

Data that’s in the short-term memory, or RAM, can be read from anywhere at almost the same speed and because it has a hard-wired connection to your system, there’s no real latency in cabling or connection.

Like short-term memory, though, RAM is not designed to stay focused forever and is ready to move on to the next task at a moment’s notice. It’s what is described in computing as “volatile,” that is, once it loses power, it forgets everything it’s learned. That makes it perfect for handling the multitude of high-speed tasks that your system throws at it on a daily basis, but it’s also why we need storage systems like hard drives and SSDs, to actually hold our information when you turn your system off.

The most common type of RAM that is sold today is DDR4, though older systems may use DDR2 or DDR3. Those simply denote the generation of RAM used in that particular system, with each successive one offering faster speeds through greater bandwidth — a higher megahertz (MHz) rating. Each generation also saw physical changes, so they are not interchangeable.

Another common term, especially in the video game space, is VRAM, or video RAM. Although once a standalone piece of technology in its own right, VRAM is today used to denote the memory available to a graphics chip or built on to a graphics card. That’s actually called Graphics DDR SDRAM, or more commonly GDDR. Most modern graphics cards will use GDDR5, though some use a newer GDDR5X standard and Nvidia’s new RTX Turing graphics cards use GDDR6.

Some niche graphics cards utilize a form of RAM called High-Bandwidth-Memory (HBM and HBM2) which has some unique performance advantages, though it is typically expensive and supply issues have meant it hasn’t seen widespread adoption.

It’s also not the only aspect of RAM that’s important. While more gigabytes of RAM can help with multitasking, you can see more improvement in the speed of your system, certain games, and applications, through using faster memory. Memory, like CPUs, has its own clock speed, which effectively controls how much data it can handle per second when combined with a few other factors. The total speed of the memory is discussed as bandwidth, in megabytes per second, but traditionally memory is marketed with a MHz speed.

Typical DDR4 memory runs between 2,133MHz and 3,000MHz but there are some that can run upwards of 4,000MHz for the fastest kits available. You would see these marketed as DDR4-2133 or similar, and sometimes with the confusing “PC” label applied too. The number that follows that is simply the MHz speed multiplied by eight and then rounded. You might see it listed as DDR4-2133 PC4-17000, for example.

Timings are another aspect of memory that can have an impact on RAM performance, though they aren’t as important as they used to be. It’s effectively the time between clock cycles, and as memory speed has increased, timings, or the latency of the memory, has increased (gotten slower) too. Typically it’s listed as several numbers separated by dashes, such as 15-15-15-35, or similar. When it comes to buying memory, timings are only really important if you’re considering high-performance memory for benchmarking or top-tier gaming and aren’t of real concern to the average consumer.

Lastly, it’s important to know about channels. Most memory sold today is at least dual-channel, and it allows two sticks of RAM of the same type and speed to operate faster by providing better access to the CPU’s memory controller. However, high-end RAM kits sold with three or four modules may support triple or even quad-channel memory.

In practical purposes, it doesn’t make a huge difference to everyday performance, but if you want to take advantage of dual or more channel memory, you just need to make sure to install it all in the right colored slots on your motherboard. Check your manual for help on that front.

• When you first turn on your computer it runs fine, but as you go about your business you notice that its performance diminishes. By lunch time, websites take minutes to load and local programs run at a snail's pace. This type of gradual deterioration of PC performance, especially with memory-intensive programs, may be caused by a RAM problem.

• Your computer randomly restarts while you are in the middle of something or freeze sporadically. It may also reboot almost immediately upon opening the desktop. This could be a sign of faulty RAM.

• A blue screen with white text flashes before restarting. Blue-screen errors are annoying because you don't even have a chance to read the error message. Bad RAM is one thing that cause them.

• Files—particularly ones you frequently access and save—seem to be inexplicably corrupted. RAM issues can lead to this problem, which can worsen over time. The file structure of your hard drive may slowly degenerate and you will no longer be able to boot your machine.

• Your attempts to install a new program repeatedly fail for unknown reasons. You try to reinstall the operating system, but keep getting odd error messages.

There are certainly a variety of problems that could cause the issues above, but faulty RAM is an often-overlooked root cause of inexplicable issues. If you have one or a combination of the above problems you are likely facing a memory issue.

Diagnosing the Problem

• If the symptoms started after you recently added more memory, the new module could be faulty. This seems obvious, but any time a problem begins after making a change, first check to see if the change caused the problem.

• Your computer may produce multiple beeps or a continuous beep when you turn it on. These beeps can indicate many different problems, including being a symptom of bad RAM. Beep codes vary depending on the manufacturer of your BIOS. You can look up the beep codes for your specific computer to figure out its specific problem.

• If you are not comfortable fixing your computer yourself, I recommend taking your computer to a local repair store rather than a big retail store. Big stores are in the business of selling additional parts, not fixing problems.

• If you are an advanced user, there are diagnostic programs that can help you figure out if you have a memory problem. Your computer may have one pre-installed by the manufacturer or you can download a third-party program. The Windows Memory Diagnostic by Microsoft is also good if you suspect memory problems on a Windows PC.

• If the above programs indicate your memory sticks are functioning, but you still suspect a RAM problem or if you need to find which memory module is the problem, you can try removing the modules and placing them in different slots.

RAM Questions