Running out of space, or still waiting on a mechanical hard drive to boot Windows, are two of the most common reasons people upgrade their storage. Adding a new SSD or extra drive is one of the more forgiving upgrades — there's no delicate socket to worry about — and it can transform boot times and general responsiveness. This guide covers choosing the right drive type, physically installing it, and getting Windows to recognise and use it properly.

Choosing the Right Drive

  • NVMe M.2 SSD: The fastest option, plugging directly into a slot on the motherboard with no cables needed. Check your motherboard has a free M.2 slot and confirm its interface generation (PCIe 3.0, 4.0, or 5.0) — a newer drive will still work in an older slot, just at the older slot's maximum speed.
  • SATA SSD: Slightly slower than NVMe but still far faster than a mechanical drive, and a good budget option or ideal if your motherboard's M.2 slots are already full. Connects via a SATA data cable and a SATA power cable from the PSU.
  • Mechanical hard drive (HDD): Best reserved today for bulk storage of files like photos, video archives, or backups, thanks to its low cost per gigabyte, rather than for running Windows or applications.
  • Capacity planning: For a Windows boot drive, 500GB is a sensible minimum today, with 1TB recommended if budget allows, since Windows updates, games, and applications grow steadily over time.

Safety warning: Always shut down fully, switch off and unplug the PSU, and discharge residual power by holding the power button for a few seconds before opening the case.

What You'll Need

  1. A Phillips-head screwdriver
  2. The new drive
  3. A SATA data cable and free SATA power connector from the PSU (for SATA drives only)
  4. The small mounting screw for an M.2 drive (usually supplied with the motherboard, sometimes with the drive)
  5. Anti-static precautions — touch bare case metal regularly

Installing an NVMe M.2 SSD

1. Locate a free M.2 slot

M.2 slots are flat, elongated slots on the motherboard, often positioned between the CPU and the first PCIe slot, or lower down the board. Many are covered by a small heatsink that needs removing first — unscrew it carefully, noting any thermal pad attached to its underside, which you'll need to keep in place or replace.

2. Fit the drive

  1. Remove the mounting screw at the far end of the slot if one is already fitted (holding a plastic standoff).
  2. Insert the M.2 drive at roughly a 30-degree angle into the slot's connector, gold contacts facing down towards the board.
  3. Press it down flat once inserted.
  4. Secure it with the mounting screw into the standoff at the correct distance along the slot (motherboards often have multiple standoff positions for different drive lengths — 2280 is the most common length).

3. Refit any heatsink

If your board or a third-party heatsink came with one, refit it over the drive, ensuring the thermal pad makes firm contact with the drive's chips, as NVMe drives can throttle performance if they overheat under sustained heavy use.

Installing a SATA SSD or Hard Drive

1. Mount the drive

  1. Locate the drive bays in your case — 2.5-inch SSDs may fit in dedicated trays, sometimes shared with 3.5-inch bays via an adapter bracket, while HDDs need a 3.5-inch bay.
  2. Slide the drive into a tray or bay and secure it with the small screws provided (either through the tray into the drive's threaded holes, or via a tool-less clip mechanism depending on your case).

2. Connect the cables

  1. Connect a SATA data cable from the drive to any free SATA port on the motherboard (labelled SATA0, SATA1, etc.).
  2. Connect a free SATA power connector from one of the PSU's cable runs to the drive's power input. Do not force it — SATA power and data connectors are L-shaped and only fit one way.

Pro tip: Note which SATA port number you use on the motherboard if you want your boot drive to appear first in the BIOS boot order — some boards prioritise lower-numbered ports by default, which can save a step later.

Reassemble and Boot

  1. Refit the side panel and reconnect all external cables.
  2. Power on the PC and enter the BIOS/UEFI (commonly Del or F2 during startup).
  3. Check the storage or boot menu page to confirm the new drive is detected, noting its listed model name.

Setting Up the Drive in Windows

If it's a new secondary drive (keeping your existing Windows installation)

  1. Open Disk Management by right-clicking the Start button and selecting it, or searching "Create and format hard disk partitions."
  2. Find the new drive, listed as "Unallocated" space, and right-click it.
  3. Select New Simple Volume, follow the wizard, choosing a drive letter and formatting it as NTFS with a quick format.
  4. The drive will now appear in File Explorer, ready to use.

If it's replacing your boot drive

  1. You'll need to either clone your existing Windows installation onto the new drive using cloning software (many SSD manufacturers provide a free tool, such as Samsung Magician or Crucial's Acronis-based tool), or perform a fresh install of Windows.
  2. For a fresh install, create Windows installation media using the Media Creation Tool from Microsoft's website on a USB drive, then boot from it (you may need to change the boot order in BIOS or use a one-time boot menu, often F12).
  3. During installation, select the new drive as the install target, ensuring you don't accidentally select the wrong disk if multiple are connected.

Troubleshooting

  • Drive not detected in BIOS: For SATA drives, check both ends of the data and power cables are firmly seated, and try a different SATA port and cable if available. For M.2 drives, reseat the drive fully and confirm the mounting screw is tightened enough to hold it flat against the slot.
  • Drive detected in BIOS but not in Windows: This is expected for a brand-new, unformatted drive — head to Disk Management as described above to initialise and format it.
  • Disk Management shows the drive as "Not Initialized": Right-click the disk (not the partition) on the left-hand column and select Initialize Disk, choosing GPT for modern systems, then proceed to create a new simple volume.
  • NVMe drive running hotter than expected or throttling under sustained load: Confirm a heatsink is fitted and making good contact, and check airflow in that area of the case isn't obstructed.
  • Cloned drive won't boot: Enter the BIOS and check the boot order lists the new drive first, and confirm the old drive is either disconnected or clearly not selected as the primary boot device, as having both connected can occasionally confuse the boot process.

When to Call a Professional

If a new drive consistently fails to appear in BIOS across multiple ports and cables, this can indicate a faulty motherboard SATA controller, a dead drive, or in rare cases a PSU issue affecting power delivery to storage devices. Similarly, if cloning software repeatedly fails or produces a drive that won't boot despite correct BIOS settings, a technician can diagnose whether the issue lies with the drive, the cloning process, or an underlying Windows installation problem.

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