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Exploring today's technology for tomorrow's possibilities

RAM vs. ROM: What’s the Difference?

Linsey Knerl
Computer memory may seem like a complicated subject, but we can help you unravel the mystery by exploring the differences between RAM (random-access memory) and ROM (read-only memory). It’s not as confusing as it seems as you’ll learn in this overview.

What is RAM?

RAM stands for “random-access memory” and is a type of volatile memory. What does volatile memory mean? RAM uses transistors to store data, and these need electricity to work. Every time you shut down your computer, anything stored on this memory disappears. In other words: RAM is easily added to or changed.
For example, let’s say you’re browsing the web and clicking between tabs. In doing so, you’ll find that the data on tabs you already visited once is instantly available. This is because the data from your browser (and its tabs) is stored in your RAM for instant retrieval. When you power down your computer or make a hard-close on your browser, all that data disappears unless you save it as a file.
RAM is generally soldered onto a small rectangular circuit board called a “stick that sits in a slot on your PC’s motherboard. You can actually see it if you crack open your computer case and look inside. Each stick may be labeled with the amount of memory included, such as 8GB or 16GB.
The number of RAM sticks in your computer depends on your motherboard. Two to four RAM slots (called DIMM slots short for dual in-line memory module) are standard for laptops due to space considerations. In desktop computers, however, the roominess of the PC case allows more variation in the number of slots.
While the standard motherboard has 4 slots, you may see anywhere from 1 to 8 DIMM slots depending on the make, model, and cost of the motherboard.

Types of RAM

The different types of RAM are:
  • DDR (double data rate)
  • DRAM (dynamic RAM)
  • SRAM (static RAM)
  • SDRAM (synchronous dynamic RAM)
Each type works a little differently. DDR, for example, disappears if it’s not continually refreshed by a program or application. DDR is also the type we think of when discussing RAM consumer computers. There are 3 kinds of DDR memory that you may encounter when shopping: DDR3, DDR3L, and DDR4.

More about DDR4 RAM

Each version of DDR improves upon the previous one. So, DDR4 is better than DDR3 in a number of ways, including speed and energy consumption (a nice perk if you’re looking to trim electricity costs). If you’re interested in finding out more about DDR4 RAM and upgrading your RAM on your own, check out our HP Tech Takes guide on how to install DDR4 RAM.

Advantages of RAM

RAM is unique in that it delivers data quickly to the user, and it can store more data than ROM. It's a quiet, energy-efficient type of memory with no moving parts. If you need to change data, store new data, or add data to your computer (in the form of files, such as music or new programs), you’ll need RAM to do it.

1. Expands

You can expand your RAM by adding more to your motherboard as long as you have the necessary DIMM slots. It’s one of the easier ways to upgrade your computing experience, too. If you’ve heard the phrase "add a stick of RAM," this is what they were talking about.
Want to know more and install some RAM yourself? Read our guide, How to Install RAM on a Motherboard, which also compares RAM vs memory and provides other helpful info.

2. Boosts overall experience

Adequate DDR4 RAM can boost your computing experience, but what happens if you don't have enough RAM for the tasks you do most? The computer has no choice but to retrieve the data from your hard drive. This is a slow process, so you'll experience lags when doing processes that shouldn't take long at all.

3. Helps with performance-focused tasks

Gaming or 3D rendering are just two examples where having enough RAM is important, since you really don’t want to have to wait for data when playing a fast-action title. 8GM is the minimum you’ll want in this situation, but it’s common to see computer enthusiasts adding more RAM to total 16GB or even 32GB of RAM.

What is ROM?

ROM (read-only memory) is a non-volatile memory type. This means it receives data and permanently writes it on a chip, and it lasts even after you turn off your computer. The data is coded to not be overwritten, so it's used for things like your printer software or your startup programs. You can't change your ROM data just by doing ordinary computer activities.
In fact, you can’t actually directly access data stored in the ROM. If you need data from the ROM, you must first transfer it to the RAM, where your processor can then access it.

Types of ROM

Most consumers won’t need to worry about the types of ROM, but it may be useful to know the terms so that you can easily identify that it is, indeed, a ROM storage option. Here are each of the types of ROM.
  • Mask ROM: ROM that is “masked off,” or covered by opaque plates called photomasks
  • PROM: Programmable read-only memory
  • EEPROM: Electronically erasable programmable read-only memory
  • EPROM: Erasable programmable read-only memory
Each type of ROM is programmed uniquely to its type, and it requires special conditions to be erased or rewritten. EPROM, for example, needs UV light to erase the data, while EEPROM uses a special circuit to rewrite data. Each type is also favored for particular uses. PROM, for example, is used in BIOS applications. Mask ROM is generally used for firmware.

Advantages of ROM

ROM data stays put once written, regardless of how you use your computer or if it’s even powered on. ROM stores many of the important processes necessary to run your computer, such as the data in your BIOS. You couldn’t even power up your computer without ROM data. ROM is also cheaper per gigabyte than RAM.

Do you need more RAM or ROM?

Is your computer glitchy? Do you have to wait a really long time when switching between programs? While your woes may be tied to more than just memory, RAM is a good place to start.
ROM is rarely the issue on a computer, and if it is, fixing it isn’t as simple as just plugging in more sticks of RAM. To know if memory really is an issue, consider the following questions.

Do my issues only happen when doing intense applications, such as gaming or editing videos?

RAM may be the cause, especially if your computer has a smaller amount to begin with. Computers need at least 4GB to do standard tasks, like web browsing and word processing. If you run many processes at once, watch a lot of videos, or participate in video calls, consider upgrading to at least 8GB. If you play games, work in video editing, or create art, you may need 16GB, at a minimum.

How much RAM do I already have?

You can find this out through the following steps:
  1. Navigate to your Startup Menu and click System Settings.
  2. You'll see a category for RAM and can select View RAM info to see what’s already installed.
  3. Your computer may or may not have room for additional RAM, but if it does, you can usually expand it yourself.
Your computer may be acting glitchy because of your processor or graphics card, too. If you’re experiencing a lot of issues, you may want to think about upgrading these components (as well as your RAM) for a full remodel. If you’re certain you don’t have enough RAM to do the tasks mentioned above, adding more is an affordable place to start.

Am I using all of my available RAM possibilities?

How many of your existing RAM slots are you using? If you have room to expand, it can't hurt to do it. Expanding your PC’s RAM usually improves your overall computing experience, and it's far less expensive than buying a new PC or laptop outright.

Things to keep in mind when shopping for a new computer

If you’re upgrading to a brand-new device, how do the specs play into the decision? While ROM isn’t something you need to think about when shopping, RAM is a serious consideration. Make sure you’re getting the required minimum amount of RAM based on your use, and remember that your needs can change over time.
It’s best to buy more RAM than you think you’ll need at first, especially if you’re getting into a new industry or hobby like gaming or photo editing.
If you can't get the maximum amount of RAM for your future needs right away, at least check that the motherboard will support future expansion. It's easier to buy what you need upfront, but your budget may require you to buy a computer with less RAM at first, then add more later.

How much RAM do I need?

Here is a rundown of how much RAM you need depending on your computer use:
  • 2GB: For the lightest of users. We don’t recommend this. You’ll quickly get frustrated at lags with even a couple of browser tabs open.
  • 4GB: Best for light users who do not run more than one or two programs at a time, and only have a few browser tabs open at once.
  • 8GB: Sweet spot for most users. Will allow you to run a video conferencing program along with several programs like Word, Excel, or Outlook at the same time. Also good for entry level gaming.
  • 16GB: Best for professional users who need to be on meetings while running heavier-duty programs. Also good for mid-range gamers.
  • 32GB: For power users who run demanding programs like CAD, video editing software, or other Adobe Creative Suite programs. Also best for high-end gamers.

Laptop RAM vs desktop RAM

While installing new RAM is a breeze on a desktop PC, the same can’t be said for laptops. It's much more difficult to expand RAM on a laptop than on a desktop. Consider how much RAM you’ll need in your laptop before you buy, especially if you don’t like the idea of opening it up or paying for a professional to do it.


Knowing the difference between ROM and RAM is useful when shopping for a new computer or simply when discussing tech issues with your IT professional. Each has a specific purpose, and your devices can’t function properly without them.
Also, as smartphones and tablets process more and more data, finding the right new gadget may depend on how much RAM it has. Purchasing a new phone or computer only to learn it lacks the memory you need may result in a severe case of buyer's remorse. You can help to avoid this regret by knowing how RAM works, researching the RAM installed on your current device, and seeing if an expansion is possible.

About the Author

Linsey Knerl is a contributing writer for HP Tech Takes. Linsey is a Midwest-based author and public speaker. She has a passion for helping consumers and small business owners do more with their resources via the latest tech solutions.

Disclosure: Our site may get a share of revenue from the sale of the products featured on this page.


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