What’s the Diff: RAM vs Storage

By | March 15th, 2016

RAM vs Hard Drives

What’s the Diff is here to explain in plain language what makes up the computer terminology we talk about, to help give you a clearer idea of what it is and how it works.

I used to work at a computer store. One of the most frequent problems my customers had involved “memory,” or the lack thereof on their computer.

In that context, “memory” usually had something to do with the computer’s storage system, not its primary memory, or RAM. RAM is important, and so is storage, but they’re two different things.

People often interchange “memory” with “storage,” and vice-versa. Statements like I have 8 gigabytes of disk or 1 terabyte of memory make computer store employees cringe, so let’s break it down and examine these two parts of your computer, how they work together and how they affect your computer’s performance.

The difference between Memory and Storage

Your computer’s main memory is called RAM. You can think of it as a workspace the computer uses to get work done. When you double-click on an app, or open a document, or, well, do much of anything, RAM gets used to store that data while the computer is working on it. Modern computers often come equipped with 4, 8 or more GB of RAM pre-installed.

There’s also storage – a hard disk drive or solid state drive where data is recorded and can stay indefinitely, to be recalled as necessary. A tax return, for example. Or an email. By comparison, RAM is “volatile” – the information that’s put in there disappears when the power is turned off or when the computer is reset. Stuff written to disk stays there (unless there’s a problem).

What is RAM?

RAM takes the form of computer chips — integrated circuits — that are either soldered directly onto the main logic board of your computer, or installed in memory modules that go in sockets on your computer’s logic board.

RAM stands for Random Access Memory. The data stored in RAM can be accessed almost instantly regardless of where in memory it is stored, so it’s very fast – milliseconds fast. RAM has a very fast path to the computer’s CPU, or central processing unit, the “brain” of the computer which does most of the work.

RAM is “random access” as opposed to “sequential access.” Data that’s accessed sequentially includes stuff that’s written to your hard disk drive, for example (it’s written in files, with a specific start location and end location). We’ll get to your hard drive storage in a moment.

If you have general purpose needs for your computer, you probably don’t need to tweak its RAM very much. In fact, depending on what computer you buy, you may very well not be able to change the RAM. (Apple has removed RAM upgradability from its laptops and most of its desktop computers, for example).

How much RAM - Mac OSHow much RAM on Mac OS (Apple Menu > About This Mac)How much RAM - Windows 10How much RAM on Windows 10 (Control Panel > System and Security > System)

If your computer is older and upgradable, putting in more RAM helps it load and use more apps, more documents and larger files without slowing down, because less data needs to be written out the disk drive.

If you work with very large files — big databases, for example, or big image files, or if the apps you work with require a large amount of memory to process their data, having more RAM in your computer can help performance.

What is Computer Storage?

Computers need some form of non-volatile storage: A place data can stay even when the computer isn’t being used, so you don’t have to reload and re-enter everything each time you use the computer. That’s the point of having storage, in addition to RAM.

Storage for the vast majority of computers in use today consists of a hard disk drive. Hard drives can provide hundreds or thousands of gigabytes of space that can be used to store applications, documents, data and all the other stuff you need to get your work done (and your computer needs to operate).

Mac OS Disk SpaceDisk Space on Mac OS (Apple Menu > About This Mac > Storage)

Windows 10 Disk SpaceDisk Space on Windows 10 (This PC > Computer)

Storage is slower than RAM. Hard disk drives are mechanical devices, so they can’t access information nearly as quickly as memory does. And storage devices in most personal computers use an interface called Serial ATA (SATA), which affects the speed at which data can move between the drive and the CPU.

So why use hard drives at all? Well, they’re cheap and plentiful.

In recent years, more computer makers have begun to offer Solid State Drives (SSDs) as a storage option, in place of, in addition to, or often combined with a conventional hard disk drive.

SSDs are much faster than hard drives, since they use integrated circuits. SSDs use a special type of memory circuitry called non-volatile RAM (NVRAM) to store data, so everything stays in place even when the computer is turned off.

Even though SSDs use memory chips instead of a mechanical platter that has to be read sequentially, they’re still slower than the computer’s RAM. That’s partly because of the performance of the memory chips that are being used, and partly also because of the bottleneck created by the interface that connects the storage device to the computer – it’s not nearly as fast as the interface RAM uses.

How RAM and Storage affect your computer’s performance

For most of us using computers for general purpose work – checking email, surfing the web, paying the bills, playing a game or two and watching Netflix – the RAM our computer comes with is as much as we’ll need. Further down the road, we might need to add a bit more to keep up with new operating system improvements, updated apps and new apps that have a heavier requirement.

If you’re planning to use your computer for more specialized work, more RAM may benefit you greatly. Examples of those sort of tasks including editing video, editing high-resolution images, recording multi-track audio, 3D rendering, large scale computations for science and engineering.

Again, depending on what computer you buy, you may not be able to upgrade your RAM. So consider this carefully the next time you buy a new computer, and make sure it’s either upgradeable or comes equipped with as much RAM as you think you’ll need.

Besides RAM, the most serious bottleneck to improving performance in your computer can be your storage. Even with plenty of RAM installed, computers need to write information and read it from the storage system – the hard drive or the SSD.

Hard drives come in different speeds and sizes. Many operate at 5400 RPM (their central axes turn at 5400 revolutions per minute). You’ll see snappier performance if you can get a 7200 RPM drive, and some specialized operating environments even call for 10,000 RPM drives. Faster drives cost more, are louder and use more power, but they exist as options.

Because they use computer chips instead of spinning disks, SSDs are faster still, and they consume less power, produce less heat and can take up less space. They’re also a lot more money per gigabyte (though the price has dropped quite dramatically in recent months) – so do what you will based on your budget and your needs.

For more about the difference between hard drives and SSDs, please check out Hard Disk Drive Versus Solid State Drive: What’s the Diff?

Your computer’s RAM can fill up: Load up a bunch of applications, open a bunch of documents, get a bunch of activities going, and RAM will be used up by each of the individual processes, or programs, that are running.

When that happens, your computer will temporarily write information it needs to keep track of to disk storage – a predefined portion of your hard drive or SSD. This is called virtual memory, and it’s a pretty standard feature of modern operating systems.

The faster your disk is, the less time it takes for the computer to read and write virtual memory. So a computer with an SSD, for example, will seem faster under load than a computer with a regular hard drive.

SSDs also take less time to load apps and documents than hard drives, too. Really, if your computer is using a hard drive, one of the best things you can do to extend its life and improve performance is replace it with an SSD.

Back up early and often

No matter how you configure your computer’s RAM and hard drive, remember to back up your device. Whether you have an SSD or a hard drive, regardless of how much RAM is installed, things will eventually slow down and stop working all together.

You don’t want to be caught without any sort of ability to recover. That’s why it’s vital to have a backup strategy in place. A good backup strategy shouldn’t be dependent on any single device, either, so even if you’re backing up to a local hard disk, a network attached storage system, a Time Capsule or some other device on your computer or local network, you’re not doing enough. Having offsite backup like Backblaze can help.

For more on best backup practices, make sure to check out Backblaze’s Backup Guide.

Next time on What’s the Diff: Time Capsule vs. Time Machine.

Still confused? Have a question? Let us know in the comments. And if you have ideas for things you’d like to see featured in future installments of What’s the Diff, please let us know!

Peter Cohen
Peter will never give you up, never let you down, never run around or desert you. He also manages the Backblaze blog.

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  • Catherine

    OMG…I’ve been RICK-ROLLED!!!!!

  • ALYSA ILIANA

    The computer can access anything stored in RAM nearly instantly. Things on the hard drive need to be located, read and sent to RAM before they can be processed. If your computer says you are low on disk space you have too many programs or files on your computer.

  • cartman94501

    When I was learning about this stuff 30-40 years ago, I was taught that RAM and disk are both random access because you can access any byte in RAM or on disk more or less instantly without having to read through the prior ones. Tape, on the other hand, is sequential access. Has the terminology changed with the times?

    • The meaning is the same, but the technology has changed – tapes to drives, and drives, increasingly, to solid state.

  • Thomas van de Hoef

    In Human Terms:
    RAM is like Short Term Memory, forgotten in an instant when you get distracted.
    Disk Storage tends to be like Long Term Memory – It may take a while to remember and sometimes is best backed up by keeping a diary or journal.