Results: 128 KB Sequential Reads
Fantastic sequential read and write performance is a trademark of modern SSDs. To measure it, we use incompressible data over a 16 GB LBA space, then test at queue depths from one to 16. We're reporting these numbers in binary (where 1 KB equals 1024) instead of decimal numbers (where 1 KB is 1000 bytes). When necessary, we're also limiting the scale of the chart to enhance readability.
128 KB Sequential Read
The y-axis starts at 300 MB/s because we need all of the separation we can get to distinguish the larger three 840 EVO drives. Samsung's 120 GB model has a funkier trajectory, starting under 400 MB/s, peaking at a queue depth of two, above the higher-capacity models, and then stumbling again at a queue depth of 16. Such is life for a drive with just eight dice to call its own.
Folding in the rest of the field, only Intel's SSD 335 working with incompressible data at low queue depths stands out.
With a single outstanding command, 100 MB/s separates the fastest and slowest SSDs. Samsung's 840 EVOs are in the thick of it.
Are you wondering which of the drives we tested fares best in our 128 KB sequential read test? Here's a break-down of the maximum observed read performance during Iometer-based benchmarking.
All four 840 EVO drives set up shop in the middle of the pack, though almost every sample lands roughly in the same ballpark. They all push past 500 MB/s at least.
