The roll-out of PCIe 4.0 support to consumer NVMe SSDs has been a long, drawn-out process so far, but it is progressing. Two waves of high-end SSDs have now hit the market, and last year we saw several brands introduce QLC-based SSDs using the now-outdated first-wave Gen4 SSD controller from Phison. More recently, PCIe 4.0 support has arrived for the mainstream mid-range market segment thanks to the ADATA XPG Gammix S50 Lite, based on the Silicon Motion SM2267 controller and TLC NAND flash memory.

The ADATA S50 Lite uses Silicon Motion's first PCie 4.0 SSD controller: the SM2267. Opting to start small, Silicon Motion has launched their mainstream SSD controller first, while their upcoming (overdue?) SM2264 will eventually be filling the high-end role.

To that end, the SM2267 serves Silicon Motion's lineup as a smaller, cheaper design aimed at mainstream consumer use cases. To accomplish this, Silicon Motion has built the SM2267 on a tried-and-true (and cheap) 28nm process and equipped the controller with 4 NAND channels, as opposed to the 12nm (or smaller) 8-channel controllers that are used in the latest high-end drives. This does limit maximum performance, but it also helps to keep costs in check, something that's especially useful during the current chip crunch.

Intel's recently-launched third generation QLC SSD (the Intel SSD 670p) uses a close relative of this controller; the SM2265 is an Intel-commissioned derivative of the SM2267 that lacks PCIe 4.0 support, but is otherwise identical in all the important ways. As we'll see from the S50 Lite's performance, the Intel 670p isn't missing out on much without that Gen4 support.

As for the subject of today's review, the ADATA XPG Gammix S50 Lite and its SM2267 controller is part of a growing trend of mainstream NVMe SSDs moving to 4-channel controllers rather than 8 channels. The capacity of individual NAND flash memory dies has grown to the point that an 8-channel controller is not necessary to get 2TB of flash connected, and the IO speed of recent generations of NAND flash is fast enough that a newer four-channel controller can match the performance of older 8-channel designs. This was first demonstrated to great effect by the SK hynix Gold P31. On paper, the Gammix S50 Lite promises more or less the same thing: performance that matches or slightly exceeds what we see from high-end PCIe Gen3 SSDs also using TLC NAND, despite working with half as many NAND channels.

ADATA XPG Gammix S50 Lite Specifications
Capacity 512 GB 1 TB 2 TB
Form Factor M.2 2280 double-sided with heatsink
Interface PCIe 4 x4, NVMe 1.4
Controller Silicon Motion SM2267
NAND Flash Intel/Micron 96L TLC
Sequential Read (MB/s) 3800 3900
Sequential Write (MB/s) 2800 3200
Random Read IOPS (4kB) 191k 380k 490k
Random Write IOPS (4kB) 510k 540k
Warranty 5 years
Write Endurance 370 TB
0.4 DWPD
740 TB
0.4 DWPD
1480 TB
0.4 DWPD
Retail Price   $139.99

ADATA equips the S50 Lite with a fairly thick heatspreader, and like most of their Gammix SSDs, that heatspreader comes already attached to the drive rather than packaged separately as with their SX series drives. Instead of using their typical thermal paste, this heatspreader is attached with what is by far the most tenacious thermal tape we've ever encountered. It is reinforced with a tight-woven stiff fabric and the adhesive was strong enough that removing the heatspreader without permanently damaging the drive required copious use of solvents instead of just a bit of gentle prying.

So while we had originally speculated that the SM2267 controller might allow the S50 Lite to be the first Gen4 SSD suitable for laptop usage (hoping for similar power efficiency to the SK hynix Gold P31), this heatspreader plus the double-sided design means the S50 Lite will be a challenge to fit into some notebooks.

The SM2267 controller actually has a slightly higher pin count than the older 8-channel SM2262(EN) controllers, but the SM2267 uses denser packaging to fit in the same footprint as their earlier 4-channel SM2263 controller. The resulting PCB layout is not at all crowded, and could have easily been made into a single-sided design like the Intel 670p, had ADATA wanted to stack 16 NAND dies per package. Any future drives that use the DRAMless SM2267XT variant certainly should be single-sided.

Our 2TB S50 Lite sample is equipped with 1GB of DDR4 DRAM—half as much as we would typically expect from a mainstream or high-end SSD. As the high-end has moved on to PCIe Gen4, we have seen an increasing number of mid-range or low-end NVMe SSDs cut back from the usual 1GB per 1TB ratio of DRAM to NAND, and with the S50 Lite that trend has crossed over to Gen4. Having half or a fourth of the usual DRAM is nowhere near as serious a handicap as an entirely DRAMless SSD design, and will generally only make a difference for very storage-intense usage with heavy multitasking—workloads that are a bit beyond the intended use case for a drive like the S50 Lite.

Also noteworthy about the S50 Lite is that ADATA announced and published specs for a 512GB model, but we've only seen the 1TB and 2TB models hit the market.

The Competition

ADATA's original Gammix S50 was a Phison E16 drive: their first flagship Gen4 drive and part of the first wave of consumer Gen4 SSDs. That has since been superseded by the Gammix S70, and the S50 Lite slots into a lower position in their product stack. Standing in for the various Phison E16 TLC drives, we have test results from the Seagate FireCuda 520. We also have the Corsair MP600 CORE representing the Phison E16 QLC drive family.

Other PCIe Gen4 drives in this review include the WD Black SN850 and Samsung 980 PRO—both high-end models that are significantly more expensive.

The rest of the drives included in this review are a variety of more mainstream PCIe Gen3 SSDs and some relatively low-end NVMe options. Highlights include the Intel 670p (almost the same controller, but with QLC), the HP EX950 and Kingston KC2500 using the previous-generation SM2262EN controller, and Microcenter's Inland Premium representing the current crop of Phison E12S drives with TLC NAND and a reduced DRAM ratio.

Trace Tests: AnandTech Storage Bench and PCMark 10
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  • Qasar - Monday, May 3, 2021 - link

    " Not a fan of freedom of speech/expression/press? " that what it is, its just his bias opinion, for some reason, he hates QLC, and seems to go to great lengths to say how bad it is.
  • Linustechtips12#6900xt - Monday, May 3, 2021 - link

    I love seeing the fights in the comment sections, honestly makes my day lol
  • FunBunny2 - Monday, May 3, 2021 - link

    " " Not a fan of freedom of speech/expression/press? " "

    a frequent complaint, esp. the Lunatic Right. the text of the US Constitution *only* promises that the Damn Gummint cannot, arbitrarily, shut you up. they can if your calling for insurrection, for instance. and it says nothing about what a private entity can do. you remember seeing signs on retail doorways - 'no solicitation allowed'? that means union organizers can't say what they want on or near the premises. it also means that Big Bad Tech can monitor and quash speech/text they find objectionable; no reason need be given. the list goes on forever.
  • GeoffreyA - Tuesday, May 4, 2021 - link

    Qasar, I think he's making a valid complaint, and fears, like many of us do, that Q will become the standard soon and T the costlier "pro" variant. QLC began with a dubious reputation and so we're resistant to its replacing something we trust. For one thing to replace something else, it must be better, not equal or weaker. Q's argument is better size and price; but, as it stands, doesn't seem to be delivering much in those areas, yet wants to usurp the throne from TLC.
  • Oxford Guy - Tuesday, May 4, 2021 - link

    'Qasar, I think he's making a valid complaint, and fears, like many of us do, that Q will become the standard soon'

    Just wait for PLC. It's coming, apparently.
  • romrunning - Tuesday, May 4, 2021 - link

    I'm inclined to agree also. I've seen the transition from SLC to MLC to TLC, and I have no doubt that soon QLC will replace even TLC (at least for consumers). TLC wasn't too far a drop-off performance-wise from MLC, but QLC is quite a bit less.

    I don't doubt that most consumers won't be able to see the difference, but I'm disappointed that we're going down the spec-tree instead of up (a lower baseline now), primarily because the mfgs want to save money.
  • Oxford Guy - Tuesday, May 4, 2021 - link

    It's amusing to see how, despite the many comments condemning QLC from other posters on this site in very recent articles, I am suddenly being singled out.

    Ad hominem won't change the facts:

    Every dollar spent on QLC is a dollar that reduces TLC production, raising TLC prices by increasing TLC scarcity. The same thing happened with MLC.

    QLC has double the voltage states for only 30% more density. That's diminished returns.

    TLC was made much more viable via the change from planar to 3D production. Remember how the Samsung 840 (planar TLC) was so unstable from voltage drift that the only solution was a kludge: re-writing the data again and again? That very serious symptom of a very troubling problem (due to the increase in voltage states in going from MLC to TLC) was solved via the introduction of 3D lithography. Where is the silver bullet for QLC? It has been produced in 3D from the beginning and yet its flaws are still quite evident.
  • Samus - Wednesday, May 5, 2021 - link

    I'm kinda with Banshee here, spreading nonsense like this is not just ignorant and counterintuitive, but dangerous. People stupid opinions can be protected by free speech but outright lies shouldn't be.
  • GeoffreyA - Wednesday, May 5, 2021 - link

    "protected by free speech but outright lies shouldn't"

    Like any principle taken too far, free speech can certainly be abused, and sow lies, discord, or hatred. That's why it's got to be bound by other rules.
  • Oxford Guy - Thursday, May 6, 2021 - link

    Free speech is a myth. All speech is subjected to censorship, including by the mind of the person producing it. The key here is that echo chambers (which aren't difficult to find on tech websites like Ars and Slashdot) are not the only solution to having community feedback.

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