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Samsung 840 EVO SSD: Tested At 120, 250, 500, And 1000 GB

Results: 4 KB Random Writes

4 KB Random Write

The performance hit finally becomes apparent when we start ripping off 4 KB random writes. Samsung's 120 GB 840 EVO trails the rest of the crew, but then again it's only expected to hit 35,000 IOPS with a boost from Turbo Write. The 250 GB model plateaus with four outstanding commands. It does hit Samsung's specified target though, settling around 66,000 IOPS. Neither the 500 GB nor the 1 TB versions quite make it to 90,000 IOPS, though the largest configuration nearly gets there at a queue depth of eight.

Without question, random write performance is extremely important. Early SSDs didn't do well in this discipline, seizing up even in lightweight workloads. Newer drives proffer more than 100x the performance of solid-state storage from 2007. However, we also see a point of diminishing returns on the desktop.

It'd be easy to single out the 120 GB 840 EVO as the family's misfit. Just remember that it's only slow by comparison. In absolute terms, it still blows away the responsiveness of a mechanical disk.