Upgrade Advice: Does Your Fast SSD Really Need SATA 6Gb/s?

Benchmark Results: 128 KB Sequential Performance

Sequential Read Performance

Examples include file copying, transcoding, game level loading, some gameplay, watching video, and editing video

In sequential reads, every drive attached to SATA 3 Gb/s offers performance between 200-300 MB/s. In this discipline, Intel's mainstream SSD 320 is on par with the high-end 6 Gb/s drives as a consequence of the ceiling imposed by second-gen SATA.

Uncorking the platform to enable 6 Gb/s data rates allows the m4, 830, and Vertex 3 to shoot up between 350-550 MB/s. Naturally, the SSD 320 doesn't see any speed-up because it's a 3 Gb/s drive.

Compressible Sequential Write Performance

When it comes to dealing with compressible data, SandForce-based SSDs enjoy a particular advantage, since the company’s architecture employs compression to achieve breakneck speeds. That explains why the 240 GB Vertex 3 wins so definitively in this test, serving as the only drive able to break through 500 MB/s.

Samsung's 256 GB 830 finishes in second with a sequential write rate around 400 MB/s, but only at queue depths higher than two. Just bear in mind that the two drives only achieve those numbers attached to SATA 6Gb/s.

If you're stuck using SATA 3Gb/s, it's more difficult to pick a winner because all of the drives are capped between 180-280 MB/s. Interestingly, Crucial's m4 is the highest performance at a queue depth of one in a 6 Gb/s configuration. But once you scale up to higher outstanding commands, you see no difference between a newer system capable of SATA 6Gb/s and one still leveraging SATA 3Gb/s.

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  • dizzy_davidh
    If you have a system that is hobbled by a lack of 6Gbs ports yet you have a good PCI spec, you can achieve 6Gbs speeds with a PCI-E card solution such as a RevoDrive. I did just that (even though my machine has 6Gbs SATA ports) as the PCI-E solution is just so simple and practical to use, and depending on which model you choose, it's speed could well exceed even what the reviewed SSDs drives can achieve.
  • outbackkid
    The bottleneck these days is the CPU, not the port. My older processor simply can't cope with the amount of data thrown at it by my Vertex 3 240 GB - watch the CPU during an application install for example, I see the CPU maxed out.
  • Anonymous
    All this talk of 6gBit upgrades is really annoying.
    I have a PC Express adapter in my Dell laptop that can only achieve averages of 20-30Mbytes to
    a western digital USB3 drive and a PCIe adaptor in my desktop system that randomly acheives 100MB
    for 3-4 seconds before slowng to a 35-40MB crawl for the rest of the transfer to another USB3 drive (reads or writes)

    These are claimed USB2 speeds not USB3.
    The whole thing seems to be a marketing scam for most people. My systems are quite new.
    6Gbit ? dont make me laugh.
    You need to seek out (if you can get it) very expensive upgrades to even get 30% of that speed
    in the real world.