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How to choose an SSD: NVMe or SATA, how much capacity and what really matters

The SSD is the part that makes the whole PC feel fast: Windows boots in seconds and games load quickly. But the “fastest” drive on the box is not always the best choice. Here is what really matters when choosing.

Sequential read speed by drive type (maximum)
HDD
≈ 150 MB/s
SATA SSD
≈ 550 MB/s
NVMe PCIe 3.0
≈ 3 500 MB/s
NVMe PCIe 4.0
≈ 7 000 MB/s
NVMe PCIe 5.0
≈ 12 000 MB/s

In games and Windows the difference between NVMe generations is small; the big jump is from a hard drive.

1. SATA or NVMe

  • SATA SSD looks like a small 2.5-inch box and is limited to about 550 MB/s. It is fine as a second drive for games and files, and the only option for an old PC without an M.2 slot.
  • NVMe SSD is a small M.2 stick in the motherboard, several times faster. For a system drive it is the default choice and usually costs about the same as SATA.
  • A hard drive is only for storage and backups: Windows and games on it feel slow.

2. PCIe generation: 3.0, 4.0 or 5.0

  • An NVMe drive works in any M.2 slot that supports NVMe, but only at the speed the board allows: a PCIe 4.0 drive in a 3.0 slot runs slower, but works fine.
  • For games and Windows, PCIe 4.0 is the best value. PCIe 5.0 drives are faster on paper, run hot and cost more, with little difference in games.
  • Check the board manual: some M.2 slots share lanes with SATA ports or other slots, and one of them may switch off.

3. How much capacity

  • 1 TB is the minimum for a gaming PC: Windows, programs and several games that each take 100 GB or more.
  • 2 TB is comfortable and often better value per gigabyte.
  • Keep 10–20% of the drive free: a full SSD slows down and wears faster.

4. What the spec sheet hides

  • DRAM cache: drives with their own DRAM keep sustained speed better. DRAM-less drives (using host memory) are fine as a secondary drive, but less good as a heavily used system drive.
  • TLC or QLC: TLC is faster and lasts longer; QLC is cheaper and its write speed drops hard when the fast cache is full. Choose TLC for the system disk.
  • TBW and warranty: the written terabytes and years the maker guarantees. 3–5 years and a few hundred TBW per terabyte is normal.
  • Heat: fast NVMe drives throttle when hot. Use the heatsink on the board or the drive (temperature guide).
  • Avoid no-name drives with unrealistic speeds and prices.

5. After installation

  1. Install the drive, check it is visible in the BIOS (BIOS guide) and, if you are installing Windows, follow the clean install guide.
  2. In Disk Management initialize it as GPT and create the partition.
  3. Check health in CrystalDiskInfo and speed in CrystalDiskMark (both in our programs article).
  4. Update the firmware from the maker’s site if there is a newer one.
  5. Keep a backup: an SSD can fail without warning, and the data cannot be recovered from a dead controller. Errors like INACCESSIBLE_BOOT_DEVICE are described in the blue screen guide.

Not sure which drive fits your build? Ask us for advice or build a balanced PC in our PC configurator.