Match A Modern SSD Up To A 6 Gb/s Controller
So, do south bridges, Platform Controller Hubs, Fusion Controller Hubs, or discrete storage controllers affect the performance of your SSD? If so, how much? At least in theory, the differences can be significant. For example, attached to Intel's DZ87KLT-75K motherboard with its Z87 Express PCH, our Samsung 840 Pro achieves a random 4 KB write rate of 101.1 MB/s. The very same SSD, connected to MSI's 790FX-GD70 with AMD's SB750 south bridge, only hit 52 MB/s. Of course, as we know from our SSD reviews, there's a big difference between the impression we get from corner case testing and the perceptible experience you get moving from one drive to another.
Overall, though, our benchmark data allows us to draw several general conclusions. On one hand, modern chipsets typically offer better SATA performance than older ones. If you're to believe the synthetics, Intel's Z87 Express and its year-old predecessor are the fastest offerings out there. Meanwhile, P55 Express and the ICH10R south bridge (taking us back to 2008) trail quite a ways back. AMD's chipsets behave similarly. The modern SB950 outclasses the older SB750. And go figure. The newer core logic supports SATA 6Gb/s data rates, while the old stuff is limited to 3 Gb/s. When you're talking about cutting-edge solid-state storage capable of bumping up against 500 MB/s in sequential transfers, of course demanding benchmarks are going to show the old 3 Gb/s stuff sucking fumes.
We might also conclude that Intel's chipsets are faster than AMD's. Again, the synthetics suggest that you're going to have a better experience on a Z87 or Z77 Express platform compared to SB950. AMD's core logic is aging (it doesn't even support PCI Express 3.0), so this isn't particularly surprising. However, you'd be hard-pressed to tell the difference by walking up to Intel- and AMD-based desktops and trying to tell the difference based on storage performance.
Discrete storage controllers soldered onto a motherboard or plugged into a PCI Express slot have their own issues. As we saw in our single-drive testing, even one fast SSD can show them to be slower than integrated storage logic. Considering that most controllers are connected to single-lane PCI Express links maxing out at a theoretical 500 MB/s, it's only natural for them to lag behind. Just try hooking up two fast drives to see what happens to their aggregate performance.
At the end of the day, while we're able to tax storage controllers in such a way that we expose their weaknesses, the practical differences between them are pretty minor. Particularly if you're paying a premium for one of the fastest SSDs out there, though, your best bet is to drop it into a system with an integrated SATA 6Gb/s-capable storage controller from AMD or Intel. Otherwise, you might not see that extra bit of speed that tends to push per-gigabyte prices up at the high-end.