Results: 128 KB Sequential Performance
Once again, we turn to Iometer to measure the most basic performance parameters.
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 help readability.
128 KB Sequential Read
Clearly, Seagate's 600 SSD and the Neutron GTX are kissing cousins. But you wouldn't know this by looking at the 128 KB sequential read results. The Seagate drive (represented by a dashed, fuchsia line) pulls strongly ahead of the GTX at lower queue depths by a massive margin. The nearly-architecturally-identical GTX delivers a comparably paltry 247 MB/s at a queue depth of one. You can see it just barely truncated off the bottom of the chart. The 600 hangs with the big boys across the board, and is even the fastest at lower QDs, if not convincingly so.
As the commands stack higher, there's a multi-drive pile-up more brutal than any you've seen at Talladega or Daytona. Blame the oppressive 6 Gb/s SATA limit for this; newer flash is wickedly fast when reading in parallel. For more distinctive sequential performance, we have to switch to writes. Every SSD tested pushes past the 500 MB/s mark at a queue depth of 16, and only Intel's SSD 335 and the Neutron GTX serve up less than 400 MB/s of throughput at queue depth of one.
128 KB Sequential Write
Sequential writes with random data help put more distance between our collection of consumer SSD representatives. Solutions with an optimum number of die (usually in the 240/256 GB range) are often capable of stunning write numbers. OCZ's Vector reigns supreme, pulling off more than 500 MB/s. To get a SATA-based drive capable of better write performance, you need a SandForce controller compressing zeros. Still, the Seagate and Corsair LAMD-powered models aren't too shabby either; the Neutron GTX achieves a scorching 487 MB/s, while the Seagate 600 writes a still-commendable 448 MB/s.
The two Intel SSDs (the SSD 335 with 20 nm NAND and the older Marvell-based SSD 510) hold down the rear guard with more modest, but still excellent numbers. You can't even tell them apart at the 320 MB/s mark.
Wondering why we're including the positively ancient SSD 510 at all? Production ceased last year, and a high price combined with abysmal random performance (compared to the younger crop of drives) destroy their value at the few places you can still find them for sale. The truth is, the obscene numbers some of these drives demonstrate might make you think that there's a massive gulf between most SSDs in terms of everyday performance. This just isn't the case, and the SSD 510 hammers our point home. You'll see what we mean as the story progresses.