When you're looking at capacities, be aware that some manufacturers overprovision memory (they reserve some cells to replace others that wear out). A 480GB SSD, for example, might have the same amount of physical memory as a 512GB drive but set aside 32GB. The same goes for 240GB drives versus 256GB drives, and 120GB models versus 128GB drives. Overprovisioned drives can handle more program/erase cycles, so manufacturers usually give them longer warranties (five years versus three).
Speaking of program/erase cycles, you can safely ignore warnings about prematurely wearing out your SSD by writing to it too often. Modern SSD controllers use wear-leveling techniques to spread write operations evenly across all the memory cells. You should expect even a non-overprovisioned SSD to have a useful life span of ten years or more under normal circumstances.
Finally, an SSD will use one of two interface technologies: SATA 3Gb/s (also marketed as SATA 2 or SATA II), or the newer and faster SATA 6Gb/s (aka SATA 3 or SATA III). Drives with the newer interface are compatible with computers outfitted with the older technology, and vice versa. But a SATA 6Gb/s drive will deliver its best performance only if it's connected to a SATA 6Gb/s interface. It is possible to add that feature to an older desktop PC with an add-in card such as Apricorn's Velocity Solo x2, provided that the computer has an available PCIe 2.0 x2 slot, PCIe 3.0 x1 slot, or better.
SSD: The upgrade that satisfies
SSDs aren't cheap, but benchmarks don't lie: Our tests show that they can pay for themselves, and then some, if you install one in an older computer or choose one for your new computer. The benefits to overall performance and even boot time will make you happy that you took the plunge.
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