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United States, Western Digital

SanDisk

Fast cards, sold for a job that is not continuous recording

Two SanDisk Extreme cards appear here, and this page exists mainly to be clear about what they are.

What Extreme cards are built for

Cameras that fill a card quickly and then stop — an action camera on a weekend, a stills camera on a holiday. High read speed gets the footage off afterwards, and the card spends most of its life idle.

What a security camera does instead

Writes continuously, or on events, and overwrites the oldest footage forever. That is a different workload, and it is what high-endurance cards exist for — rated in hours of continuous recording rather than in megabytes per second.

For event recording, an Extreme card lasts years and costs less. For 24/7 continuous recording, an endurance card is the correct product, and SanDisk makes one that is not in this catalog.

The number to ignore

190 MB/s is a read speed. What matters to a camera is writing: SanDisk states up to 90 MB/s for the 128 GB card and 130 MB/s for the 256 GB, and both are rated V30, meaning at least 30 MB/s sustained. Even a 4K stream needs only a few megabytes per second: speed is not a reason to choose between these cards, endurance is.

How cards actually fail

Silently. A worn card accepts the write and loses it, the camera reports a healthy card, and nothing is recorded. Replace cards in continuously-recording cameras on a schedule rather than on symptoms.

Every SanDisk part we have reviewed

  • SanDisk Extreme 128 GB microSDXC card with adapter

    SanDisk Extreme microSDXC 128 GB

    A fast, widely available 128 GB card that most cameras accept. It is sold for action cameras rather than for continuous surveillance, and the distinction matters more than the speed figure does.

    Capacity
    128 GB
    Read speed
    Up to 190 MB/s, stated by SanDisk
    Write speed
    Up to 90 MB/s, rated V30, stated by SanDisk
    Class
    A2 application performance
    Supplied
    SD adapter
    Endurance
    Standard — not a high-endurance card
    Amazon reference
    B09X7BK27V
    EAN
    0619659188450
    • 190 MB/s read stated by SanDisk: footage copies to a computer quickly
    • 128 GB is accepted by almost every camera, including older ones
    • Not a high-endurance card — it is built for bursts, not for being overwritten daily

    Best for: A camera recording on events rather than continuously, where the card is written to a few times a day.

    ≈ $41
    Check price on Amazon
  • SanDisk Extreme 256 GB microSDXC card

    SanDisk Extreme microSDXC 256 GB

    Twice the capacity of the 128 GB card, which in a camera translates directly into twice the days of history before the oldest footage is overwritten.

    Capacity
    256 GB
    Read speed
    Up to 190 MB/s, stated by SanDisk
    Write speed
    Up to 130 MB/s, rated V30, stated by SanDisk
    Class
    A2 application performance
    Supplied
    SD adapter
    Endurance
    Standard — not a high-endurance card
    Amazon reference
    B09X7CRKRZ
    EAN
    0619659188504
    • Doubles the retention window over a 128 GB card
    • Same SanDisk build and 190 MB/s read figure
    • Some older cameras cap at 128 GB — check before buying

    Best for: A camera whose card fills before you get round to looking at it.

    ≈ $66
    Check price on Amazon