Final Words - The ADATA Premier SP550 SSD Review: A Second Look At Silicon Motion's SM2256 Controlle

Final Words

Wrapping things up, I want to return to the broader question of what the ADATA SP550 does for the SM2256's reputation. In short, it helps a lot. The SM2256 clearly isn't the blockbuster that the SM2246EN controller was and isn't fully living up to the original expectations, but it does now have a place in the market.

To that end the ADATA Premier SP550 takes shape as a properly working implementation of an SM2256-based SSD, without the ugly surprises of the Crucial BX200. Write speeds - both sequential and random - are an acute weakness, though this admittedly is nothing new for a low-end TLC drives and at this point is becoming a known trade-off to reach lower prices. Unfortunately this also means that it still lags behind the prototype that used Samsung NAND and that it rarely pulls ahead of the pack of retail competitors. Meanwhile latency is consistently worse than drives based on other controller architectures that have multi-core processors.

The unexpected bright spot is that the SP550 exhibits relatively little performance degradation from a full drive. On the ATSB Light and Heavy tests the SP550's average data rate is lower than that of the OCZ Trion 100 when the test is run on an empty drive, but the SP550 comes out ahead when the drives are full. This effect also shows up when comparing the random write test against the steady-state performance: the SP550 is in last place on the shorter test but ranks much higher on the longer test. This is an important advantage for the 120GB model, which is the easiest to accidentally fill up. Since the 120GB SP550 is also the cheapest 120GB SSD at the moment, it's a reasonable pick for consumers trying to save every dollar possible.

At higher capacities it is much easier to justify spending a few dollars more for improved performance, and it's much easier to keep some free space on the drive. The 960GB model in particular won't make sense unless its price comes down substantially; that capacity was released more recently but probably can't compete against newer Phison drives, let alone the MLC-based Mushkin Reactor 1TB that is only $10 more. In the 480GB range the OCZ Trion 100 is priced very close and performs close albeit with different strengths and weaknesses. But again MLC drives like PNY's CS2211 aren't that much more expensive. Otherwise in the 240GB class there's not much that can compete with the SP550's price, and none of them can clearly beat it on performance.

Ultimately the bottom of the SSD market is crowded and it's hard to make a product stand out, especially as the limiting factor in both cost and performance is frequently the NAND. No value drive is without its faults and there's no clear top performer in this segment. But the ADATA SP550 does manage to stand out unambiguously with the best pricing at 120GB and 240GB while not earning notoriety for its performance. We can't reasonably demand more than that from a value drive.

As for the SM2256 controller, it's clear that Silicon Motion is learning to deal with the challenges of managing TLC flash, and many of the remaining weaknesses exhibited by the SP550 can be blamed on the limitations of the flash rather than the controller. For the impending transition to 3D NAND, the SM2246EN controller will be sticking around for MLC drives, but the SM2256 will be updated to SM2258 for 3D TLC. This suggests that Silicon Motion may be addressing more shortcomings in order to be ready to play a bigger role in the budget TLC SSD market with the next generation of drives.

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