The ADATA Premier SP550 SSD Review: A Second Look At Silicon Motion's SM2256 Controller
by Billy Tallis on March 23, 2016 8:30 AM ESTFinal 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.
| Value SSD Price Comparison | ||||
| Drive | 960GB | 480GB | 240GB | 120GB |
| ADATA SP550 | $219.99 | $112.99 | $57.99 | $38.99 |
| PNY CS1311 | $229.99 | $119.99 | $59.99 | $39.99 |
| OCZ Trion 100 | $199.99 | $114.99 | $64.95 | $54.99 |
| OCZ Trion 150 | $255.99 | $133.49 | $72.26 | $52.96 |
| Crucial BX200 | $259.27 | $128.50 | $64.99 | |
| SanDisk Ultra II | $224.65 | $129.99 | $74.99 | $54.99 |
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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zmeul - Wednesday, March 23, 2016 - link
I have the 120GB version and I'm disapointed in it - after just one month it started showing cell voltage drift and on the 2nd month it gotten worse: https://i.imgur.com/l3zonQn.pngnote: it's on a SATA2
A-Data offers no FW update for this drive
hojnikb - Wednesday, March 23, 2016 - link
Thats pretty much what you can expect with any sub 20nm TLC drive.zmeul - Wednesday, March 23, 2016 - link
well, I wish I knew that before I bought itbut neither Anand or any other site does this kind of "over time" testing
Samus - Thursday, March 24, 2016 - link
Basically you've found out first hand: AVOID any TLC drive, even TLC VNAND from Samsung isn't immune to what you are experiencing. At least you only spent $40. I still think the BX100 and OCZ ARC 100 are\were the best value, but they've spiked in price because they are no longer in production and the BX200\Trion 100/150 are a joke. My cheap go to drives now are Sandisk SSD Plus. Super cheap drive, still MLC, and suspect a reliable Marvell controller. Even the Sandisk Z400s is a reliable drive if you can get over the pretty poor performance...at least it isn't TLC performance.The laws of physics are being toyed with using NAND in TLC mode. You can't reliable store 3 values in a binary state. My childish layman's explanation goes like this: With SLC it was simple because if it was "on" it was a 1. With MLC if it was "on" it was a 1 and if it was "off" it was a 1. Using TLC, if its "on" it's a 1 if it's "off" its a 1 and if its "half" it's a 1. LOL
hojnikb - Thursday, March 24, 2016 - link
Actually, vnand tlc is just fine and possibly better than ~15nm MLC.Much larger cells offset the 3 bit per cell disadvantage.
Samus - Thursday, March 24, 2016 - link
I get that it's 40nm, so "leakage" isn't really an issue, but it still suffers from TLC's inherently poor write performance. I still prefer MLC. Especially since, as it stands right now, MLC and TLC drives are virtually the same price. I still pickup old Crucial M500's and Intel SSD320/X25-M's...and occasionally you can find new M500's in retail (Microcenter has the M550 256GB models for $60 right now)Well, they DID. I bought the last 5 at my local store I guess. http://www.microcenter.com/product/453561/256GB_SA...
They have the M500 240GB new for $67.99. Quality Marvell controller, MLC NAND, proven firmware and reliability. Until TLC drives are half that price for the same capacity I don't see what the big deal is.
KAlmquist - Thursday, March 24, 2016 - link
I'm have a hard time believing that 16nm TLC NAND is a good idea. The problems that Samsung has had with data degradation on the 840 EVO suggests that even with 19nm TLC NAND the cell size is too small. While the reviewed drive is priced attractively, I'd be more inclined to buy an MLC drive, or the Samsung EVO 850, which is TLC but with a large cell size.LarsBars - Thursday, March 24, 2016 - link
The MU02 firmware update for the Crucial BX200 resolved the strange ATTO plots that were mentioned in this review. At least for me.jabber - Friday, March 25, 2016 - link
Mmmmm the BX200. The one I got in to test finally bottomed out at a super 40MBps write speed. That was about 6 weeks ago with the latest firmware then. BX200 = Junk. The BX100, now that was and still is a quality drive.bogdan_kr - Saturday, March 26, 2016 - link
@Billy TallisI would like to ask about AnandTech Storage Bench - Light. How long (typically) does it take to finish this bench?
I mean I can see it is designed to read and write about 41GB of data. SP550 480GB finished it with 299.02 MB/s average data rate score so does that mean it took about 140 seconds?