RAM vs. SSD: What are the Differences?


RAM vs. SSD: What are the Differences?

Random access memory (RAM) is a type of flash memory that your computer uses to store session data while it processes all the information you’re inputting. Solid-state drives (SSDs) are also a type of flash memory, but the two are nothing alike and share very few traits.

Broadly speaking, RAM is used for temporary files and is wiped when your session ends, while your SSD will be used for permanent file storage. Let’s look at the history of these two memory types and how they differ.

RAM vs. SSD: A Side-By-Side Comparison

Memory TypeFlashNAND Flash
Connection TypeDIMM, SIMM, or RIMMSATA, PCIe, M. 2, U. 2, mSATA, SATA Express

RAM vs. SSD: What’s the Difference?

RAM and SSD are both types of memory that are used in full-sized desktop computers. Both are types of flash memory, however that’s really the only thing that is similar between them. In all other factors, RAM and SSDs are so different that they wouldn’t even be recognizable by ports made for the other type of memory.

What is RAM?

RAM stands for “random access memory,” and like the name would imply, your computer uses this memory to store random files and information it comes across during your session.

RAM uses a type of memory that’s referred to as being “volatile.” “Volatile” means that your PC is going to wipe the memory every time you shut your computer down. However, we have to make an addendum as Windows 10 and Windows 11 have a feature called “fast startup” that saves session information when you close your computer down and prevents the computer from shutting down entirely and wiping your RAM. Once you’ve turned off “fast startup,” your RAM will be wiped every time you shut your computer down.

The reason your RAM gets wiped when you shut your computer down is that RAM is a temporary storage center for storing “volatile” data. For instance, when you load a webpage, some of the data relating to the webpage is stored in your RAM, like the website’s logo. Then, when you navigate back to that webpage during the same session, your computer displays the website’s logo directly from the RAM instead of having to download it from the server again.

This allows your computer to not only store the information it needs to run programs but also allows it to multitask. When you shift from one application to another, the state of the application is saved in your RAM. Then, when you switch back to that application it will reload the application based on the dynamic save-state it stored when you last used the program.

For instance, if you’re writing a term paper, when you tab away from your word processor, your computer saves all the data from your word processor into the RAM. This includes its current state (what is on the screen) and all the document information (what isn’t on the screen.) This way, when your computer reloads after you’re finished with additional research or other work, you can fluidly move right back to writing.

RAM is a necessary computer component as it’s here that your computer will store all the necessary files it needs to run your operating system and programs. If a motherboard is turned on with no RAM, it will give you a postcode indicating that the PC has no RAM component installed and the startup will fail.

The installation of dual-channel RAM
Your computer’s RAM is volatile memory that will store data in the short-term.

How Does RAM Affect Speed and Latency?

When it comes to RAM, speed and latency are the most important technologies. Your RAM has to process an immense amount of data and it has to do so very quickly. With the world at our fingertips like it has been, many people are terrible at waiting patiently for things to load like we had to do in the yonder years of dial-up. Thus, it’s crucial for a RAM stick to be able to write and access data within seconds.

RAM performance is measured using a combination of two different metrics: clock speed and CAS latency. Column Address Strobe (CAS) latency is the number of clock cycles it takes for data written to the RAM to become available to read while the clock speed is the number of clock cycles a stick of RAM is able to perform per second.

There is a lot of misinformation going around about RAM speed metrics. Many users erroneously believe that the speed is based solely on the clock speed and CAS latency is just a negative metric that displays problematic information that users will want to know. However, CAS latency is just as important as clock speed and it’s not a “warning label.” It’s just a metric used to measure information about the chips.

Crucial, a popular RAM manufacturer, gives two examples of how clock speed and CAS latency are deeply intertwined regarding the overall speed of a RAM stick.

Put simply, if two RAM sticks have the same clock speed, choose the one with less CAS latency. If they have the same CAS latency, choose the one with the higher clock speed. If the stick is the loser in both clock speed and CAS latency, choose the winner!

Will Upgrading My RAM Make My Computer Faster?

Upgrading your RAM can make your computer faster and allow it to more effectively process large amounts of information and multitask. Typically, when people look to upgrade their RAM, they look at upgrading the amount of RAM installed on their PC.

While this will technically make your computer faster—it will allow the computer to save more information to the RAM, thus allowing it to move between programs faster—the amount of memory installed isn’t the only important feature.

You’ll first want to consider whether the RAM you want to purchase is compatible with your PC. Most PCs use DDR4 RAM slots, but people with older computers may still have DDR3 slots for installation. Upgrading to DDR4 RAM isn’t possible if your motherboard has DDR3 slots.

You’ll also want to check to make sure that the RAM you’re buying is an actual upgrade and not a lateral transfer. You’ll need to check the clock speed and CAS latency in the technical specifications. Remember: your computer won’t actually process information faster unless the unit has a higher clock speed or better CAS latency. If the clock speed and CAS latency are the same, all that changes is the amount of information stored, not the speed it’s written or accessed.

What is an SSD?

SSD stands for “solid-state drive” and this is a type of non-volatile flash memory used for permanent storage. The SSD is the successor to the hard disk drive (HDD) and offers faster, more reliable, and safer data storage than the typical HDD.

To understand why the SSD is so popular and what makes it better, we have to first explore the inner workings of its predecessor, the HDD.

HDDs use a spinning magnetic disk with a disk head that writes magnetic poles into the disk. The disk isn’t scratched or permanently altered when the disk head writes a pole onto the disk. So, the disk can be formatted and rewritten easily.

When the disk needs to be read, the disk head will be moved back to the exact location on the spinning disk where the information is held. Then it will read the disk back, transforming the magnetic poles into a series of ones and zeroes that become binary code that is readable by your CPU to display the information you seek.

As most engineers and other computer geeks will tell you, HDDs are notorious for failing and, when they do, all the information on the disk is lost. This is one of the most compelling reasons that most people switch from HDDs to SSDs; they want to preserve their information.

SSDs are more reliable than HDDs because they don’t have as many moving parts. While HDDs use a spinning disk to read and write information, SSDs use flash memory. Flash memory doesn’t require a physical read-write system as the information is stored electronically. On the smallest scale, flash drives are an example of consumer-level flash memory. SSDs use more advanced technology than flash drives and connect to different ports, but the systems inside are similar.

SSDs came after HDDs and are used for permanent memory storage.

Storage Medium vs. Storage Device

The easiest way to think about it is the difference between a device and a medium. Much like in art, computer components use different “mediums” to describe their systematic processes. Flash storage is a storage medium—a type of data storing method.  An SSD is a storage device. “SSD” refers to a specific use of flash memory as a non-volatile computer storage method. A flash drive is a different kind of storage device that uses the flash memory medium.

Since flash memory stores data electronically, its ability to read and write information is much faster than a traditional HDD. When an HDD reads its memory back, it must first find the required information on the disk and position the disk head in the right place to read the information. Then the disk has to move the disk head over all the information and process it as binary code.

Flash storage does all of this electronically. Unlike the HDD, flash storage is “alive” in its own way. It’s capable of reading and writing data on a code level and doesn’t usually require the computer to read back binary off of a spinning magnetic saucer.

Do SSDs Make Your Computer Faster?

When upgrading from an HDD to an SSD, most users will experience a huge boost in their system’s overall speed and performance. This bump in speed is largely due to the SSD’s faster read and write times and the ease of accessing electronic information compared to an HDD.

However, SSDs do not necessarily increase your computer’s speed if you already have an SSD. If you already have an SSD it is possible to further increase your speed by upgrading your SSD. But upgrading from an SSD to a faster SSD requires more mechanical knowledge than upgrading from an HDD to an SSD; going from an HDD to an SSD, the SSD will always be faster. But, between two SSDs, you’ll have to look at their technical specifications to understand what you’re upgrading.

Storage Disk Size

The first thing you’ll see when you’re looking at upgrading your SSD is going to be the size of the storage disk. SSDs are measured in Gigabytes and Terabytes, typically with disk sizes as small as just a few gigabytes and as large as eight or more terabytes.

This is the easiest upgrade to make when looking at SSDs because it’s generally the first thing any company is going to tell you about a storage disk. However, if you’re looking for more speed rather than more storage, you’ll need to look at more complicated specifications.

Form Factor

The first thing you’ll want to look at after assessing how much storage you’ll need is the SSD’s form factor. SSDs come in multiple forms, including PCIe chips that are about half the size of a stick of RAM and 2.5” hard disks that are around the same size as a laptop hard drive.

M.2 SSDs, or the ones that look like RAM but plug into the PCIe slot, are newer, faster, and more compact, allowing them to be used by microcomputer manufacturers and enthusiasts who have limited space in their computer towers.


The SSD interface is also worth considering. 2.5” SSDs will typically use a Serial ATA or SATA connection to interface with the motherboard, but PCIe cards will need to be plugged into a PCIe slot.

Check your motherboard to see whether you have available PCIe slots to upgrade with. Most standalone motherboards have two to four PCIe slots for expansions. However, a lot of graphics cards are “dual-slot” cards, meaning that they take up the space of two slots despite only using one of the connectors.

If you don’t have any available PCIe slots, you’ll need to get a SATA SSD. You may also run into issues if you have an older motherboard that still has regular PCI slots. While many SSDs will be able to interface with both PCI and PCIe slots, you’ll need to choose an SSD that is compatible with the slots you have available. So, it’s crucial to check what kind of expansion slots you have available.

Read Speed

There are two types of read speeds in the world of SSDs: sequential and random. Sequential speed is how fast your SSD can read data written to the hard drive in sequential order, while the random read speed is how fast it can read data that was stored in random order.

Write Speed

The write speed is how fast an SSD can write data to its memory. Like read speeds, write speeds have sequential and random speeds. Sequential is how fast the drive can write to the drive when all the information is stored in sequential blocks, while the random order is responsible for writing data stored in non-sequential blocks.

Endurance Rating

While SSDs are remarkably more durable than HDDs, they do have an upper limit of usage. SSDs have a maximum number of times the data can be erased and rewritten. Meaning when you delete data from your SSD, you’re using up a non-zero amount of its lifetime write cycles. An SSD’s endurance rating is measured in Terabytes Written (TBW) and indicates the maximum amount of data able to be stored over the device’s lifetime before the blocks become less reliable and more susceptible to corruption and other data loss.


IOPS stands for “Input/Output Per Second,” and this is the speed that your SSD is able to read and process random data packets like webpages, game save files, and documents.

Memory Cell Type

SSDs also feature a variety of memory cell types that the devices use to store their data. The four main types of memory cell types are “Single Level Cells” (SLC), “Multi-Level Cells” (MLC), “Enterprise Multi-Level Cell” (eMLC), and “Triple-Level Cells” (TLC).

SLC SSDs are the most expensive and most reliable. They’re typically only used by enterprise-level companies that can afford the high price tag. MLC drives are cheaper but less reliable than SLC drives. However, eMLC SSDs offer an enterprise-quality drive using MLC technology.

TLC drives can write up to three bits of data to each drive, but sacrifice a lot of the speed we typically see from SSDs (though they’re still worlds faster than HDDs).

Considering all these factors when upgrading between SSDs will help you choose a product that is actually faster than the one you already have installed.

RAM vs. SSD: 5 Must-Know Facts

  • RAM and SSD are two different kinds of computer memory.
  • RAM is called “volatile memory” because the data is wiped when the computer powers down.
  • SSDs are “non-volatile” and data saved to their memory is not deleted.
  • SSDs have a finite number of data cycles before the memory begins to risk becoming corrupted by further use.
  • Computer memory uses more than one metric to determine the speed of the unit.

Final Thoughts

Computer speed is important to many people, especially those who use their computers for work. So, do a lot of research before you upgrade your PC to ensure that the upgrades you’re making will impact the metrics you’re looking to see improvement in!


Frequently Asked Questions

What is RAM?

RAM stands for random Access Memory and it’s a type of volatile flash memory that your computer uses to store session-specific application data and files.

What is an SSD?

An SSD is a type of computer hard disk that uses flash memory to store permanent files and information that you want to access offline.

Does more RAM make your computer faster?

Adding more RAM does not make your computer faster. It only increases the amount of data the computer can store and access.

Does installing an SSD make your computer faster?

SSDs have faster read and write speeds than HDDs. You’ll see an immediate speed boost when switching from an HDD to an SSD. Further upgrades require knowledge of SSD components and their functionality.

Are SSDs fail-safe?

No computer component is entirely fail-safe. However, SSDs have a publishable and verifiable lifespan that can be produced and reproduced in empirical testing easily. So, you’ll be able to tell when your SSD needs to be replaced very easily.

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