The three ways to add storage to a PC

You can add storage to a PC in three ways: install a new internal drive (SSD or hard drive), connect an external USB drive, or use cloud storage. Internal drives are fastest and permanent; external drives are portable and don't open your case; cloud storage lives online and syncs across devices. Which one you choose depends on how much space you need, how fast you want the data to be, and whether you want to move the drive between computers.

Most people who open their PC for the first time choose an internal SSD because it's the same speed as the drive already inside, costs less per gigabyte than external drives, and doesn't clutter your desk. But if you don't want to open your case, an external SSD is faster than a hard drive and works when ready. If you need backup rather than working storage, cloud storage through OneDrive, Google Drive, or Backblaze costs less and protects your files if your PC fails.

Key Takeaways

  • Internal SSDs are the fastest and cheapest way to add permanent storage, but require opening your PC case and identifying which slot your motherboard has (M.2 or 2.5-inch SATA).
  • External SSDs connected by USB are slower than internal drives but work when ready and let you move files between computers without opening your case.
  • Hard drives (internal or external) cost less per gigabyte than SSDs but are significantly slower and more fragile if moved or dropped.
  • Cloud storage through OneDrive, Google Drive, or Backblaze is best for backup and syncing files across devices, not for running programs or games.
  • Before buying, check your motherboard manual or use CPU-Z to see which internal slots are available and whether your power supply has spare connectors.

Installing an internal SSD — the fastest and cheapest option

An internal SSD is the best choice if you want speed and low cost. SSDs have no moving parts, so they're faster than hard drives and less likely to fail. A 1TB internal SSD costs between $50 and $100 depending on the brand and speed; the same capacity in an external SSD costs $80 to $150. Once installed, an internal drive is invisible and permanent — you don't plug it in or move it.

Most modern PCs use an M.2 slot, which looks like a thin horizontal slot on the motherboard and holds a drive the size of a stick of gum. Older PCs use a 2.5-inch SATA slot, which is larger and requires a cable. Check your motherboard manual or use the free tool CPU-Z (read from cpuid.com) to see which type you have and how many empty slots are available. If you're not sure, take a photo of your motherboard and post it in a PC building forum — people will identify the slots for you in minutes.

Installation takes 10 minutes. Power off your PC completely, unplug it, and touch a metal part of the case to discharge static electricity. Remove the side panel (usually two or four screws). Locate the empty M.2 or SATA slot. For M.2: insert the drive at a 30-degree angle, then press down and screw it in place. For SATA: slide the drive into the slot horizontally, connect the data cable to the motherboard, and connect the power cable from your power supply. Close the case, plug in the PC, and turn it on. Windows will recognize the new drive automatically.

Using an external SSD — no case opening required

An external SSD is the right choice if you don't want to open your PC or if you move files between computers often. External SSDs connect by USB-C or USB 3.0 and are much faster than external hard drives — typically 400 to 1000 MB per second versus 100 to 150 MB per second. A 1TB external SSD costs $80 to $150 and works the moment you plug it in; Windows treats it like a regular folder.

Popular external SSDs include the Samsung T7 (USB-C, very fast), the WD My Passport SSD (USB-C, reliable), and the Crucial X6 (USB-C, budget-friendly). All three are durable enough to carry in a bag. Plug the drive into any USB port on your back panel if possible — back ports are usually faster than front ports. Windows will ask you to format the drive the first time you connect it; choose NTFS format if you only use Windows, or exFAT if you share files with Mac computers.

External SSDs are slower than internal drives because USB has a speed limit, but the difference is only noticeable if you're moving hundreds of gigabytes at once. For everyday use — saving documents, storing photos, running backups — you won't feel the difference. If you plan to run programs or games from the external drive, an internal SSD is faster.

Hard drives — cheaper but slower

Hard drives cost less per gigabyte than SSDs: a 2TB internal hard drive costs $40 to $60, and a 2TB external hard drive costs $50 to $80. But they're significantly slower. A hard drive reads at 100 to 200 MB per second; an SSD reads at 500 to 7000 MB per second depending on the type. That means copying a 50GB file takes 4 minutes on a hard drive and 10 seconds on an SSD.

Hard drives also have moving parts, so they fail more often and break if dropped. If you're storing files you rarely access — old photos, archived documents, backups — a hard drive is acceptable. If you're running programs, games, or video editing from the drive, an SSD is worth the extra cost. Internal hard drives require the same installation as internal SSDs (M.2 or SATA slot), but they're larger and need a power cable.

External hard drives are portable but fragile. If you drop one, the read head can crash into the spinning platter and destroy the drive. If you need portable storage, an external SSD is safer and only slightly more expensive.

Cloud storage — for backup and syncing

Cloud storage is not the same as adding a drive to your PC. Instead, it stores files on a company's servers and syncs them to your PC automatically. OneDrive (included free with Windows), Google Drive, and Backblaze all work this way. You get a folder on your PC; anything you put in that folder uploads to the cloud and appears on your phone, tablet, or another computer.

Cloud storage is best for backup and syncing, not for adding working storage. If your PC's drive fails, your files are safe in the cloud. If you work on a document on your laptop and then sit down at your desktop, the latest version is already there. But cloud storage is slower than a local drive because it has to talk to the internet, so don't expect to run programs or games from it.

OneDrive gives you 5GB free and 100GB for $2 per month. Google Drive gives you 15GB free and 100GB for $2 per month. Backblaze is $7 per month for unlimited backup of everything on your PC. If you just need to sync a few folders between devices, OneDrive or Google Drive is enough. If you want a full backup in case your PC fails, Backblaze is cheaper than buying an external drive.

Checking your PC before you buy

Before you buy a drive, find out what your PC can hold. read and run CPU-Z (free from cpuid.com). Go to the Mainboard tab and write down your motherboard model. Search that model number on the manufacturer's website (usually ASUS, MSI, Gigabyte, or ASRock) and read the manual. The manual will show you how many M.2 slots and SATA slots you have and which ones are available.

If you're adding an internal drive, also check your power supply. Open your case and look at the power supply unit (the metal box with cables coming out). If you're adding a hard drive or a second SSD, count the spare SATA power cables — they look like flat connectors with four pins. If you're adding an M.2 SSD, you don't need an extra power cable. If you have no spare SATA cables and you need one, you'll have to buy a power supply upgrade, which costs $50 to $150.

If you're not comfortable opening your case, take your PC to a local computer shop and ask them to check for you. Most shops will do this for free or for $20 to $30. They can also install the drive for you if you buy it from them or bring it in.

Frequently Asked Questions

Can I use both an internal SSD and an external drive at the same time?

Yes. You can install an internal SSD and also plug in an external drive. Windows will treat them as separate drives and you can move files between them. This is common — people add an internal SSD for speed and an external drive for backup.

What's the difference between M.2 and SATA?

M.2 is a newer, smaller slot that's faster and doesn't need a separate power cable. SATA is older and larger and requires both a data cable and a power cable. Most PCs made after 2015 have M.2 slots. If your motherboard has both, M.2 is the better choice.

Do I need to reinstall Windows if I add a new drive?

No. Windows stays on your existing drive. A new drive appears as an empty folder in File Explorer and you can start using it when ready. You only reinstall Windows if you're replacing your existing drive, not adding a new one.

Is it safe to open my PC case?

Yes, if you follow basic precautions. Power off completely, unplug the PC, and touch a metal part of the case before touching components inside. This discharges static electricity that can damage parts. Don't touch the gold connectors on the drive or the motherboard. If you're nervous, a computer shop can do it for $30 to $50.

What size drive should I buy?

Most people buy 500GB to 1TB for everyday use. If you store a lot of video, photos, or games, buy 2TB. If you're not sure, start with 500GB — you can always add another drive later. Don't buy more than you think you'll use; larger drives cost more and you're paying for space you won't fill.