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The rationale for our endurance test hasn't changed, which is why these intros tend to channel the same theme. Solid-state drives use flash memory that has limited write endurance. Every time data is written, the physical structure of the NAND cells degrades. The cells eventually erode to the point where they become unusable, forcing SSDs to poach replacement blocks from their overprovisioned spare areas.This dynamic raises several questions. What happens when drives run out of overprovisioned area? How long does it take? And do they slow down along the way? We're seeking answers in our endurance experiment, which is subjecting a collection of drives—the Corsair Neutron GTX 240GB, Intel 335 Series 240GB, Kingston HyperX 3K 240GB, Samsung 840 Series 250GB, and Samsung 840 Pro 256GB—to a merciless onslaught of writes......The 840 Series reported its first reallocated sectors after 100TB of writes, and it's been burning through flash steadily ever since. After 500TB of writes, the 840 Series is up to 1722 reallocated sectors. Meanwhile, the other SSDs have only a handful of flash failures between them. And two of the drives, the Neutron GTX and the HyperX 3K being tested with compressible data, haven't logged a single reallocated sector.Samsung won't confirm the size of the 840 Series' sectors, but we're pretty sure it's 1.5MB. That means the drive has lost 2.5GB of its total flash capacity already. Fortunately, those flash failures haven't affected the amount of user-accessible capacity. The 840 Series has extra overprovisioned spare area specifically to offset the lower endurance of its TLC NAND. So far, at least, those flash reserves seem to be sufficient.
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Topic: The SSD Endurance Experiment: 500TB update (Read 839 times)
