The ADATA GAMMIX S50 Lite 2TB SSD Review: Mainstream PCIe Gen4

Mixed IO Performance

For details on our mixed IO tests, please see the overview of our 2021 Consumer SSD Benchmark Suite.

Mixed Random IO	Throughput	Power	Efficiency
Mixed Sequential IO	Throughput	Power	Efficiency

The ADATA XPG Gammix S50 Lite has mediocre overall performance on the mixed random IO test and comes in last place among this batch of drives for the mixed sequential IO test. These results aren't too surprising at this point; the mixed IO tests are both conducted on a mostly-full drive without restricting the test to a narrow slice of the drive, and we've already seen that these conditions bring out the worst in the S50 Lite.

Mixed Random IO	ADATA XPG Gammix S50 Lite 2TBIntel SSD 670p 2TBSamsung 970 EVO Plus 1TBSamsung SSD 980 1TBSamsung 980 PRO 2TBHP EX950 2TBSeagate FireCuda 520 1TBInland Premium 2TBKingston KC2500 1TBCorsair MP600 CORE 2TBSK hynix Gold P31 1TBWD Black SN750 1TBWD Black SN850 1TB
Mixed Sequential IO	ADATA XPG Gammix S50 Lite 2TBIntel SSD 670p 2TBSamsung 970 EVO Plus 1TBSamsung SSD 980 1TBSamsung 980 PRO 2TBHP EX950 2TBSeagate FireCuda 520 1TBInland Premium 2TBKingston KC2500 1TBCorsair MP600 CORE 2TBSK hynix Gold P31 1TBWD Black SN750 1TBWD Black SN850 1TB

On the mixed random IO test, the S50 Lite is at least fairly consistent; once the workload has more than about 30% writes there isn't much change in the performance. By contrast, the mixed sequential IO test results are a mess, with performance bouncing around with no clear pattern. SLC cache overflow is probably the primary factor here, but it ends up being less consistent than the results from the sustained sequential write test. The fact that we're testing four independent streams of sequential IO is probably also a very poor match for the kind of IO patterns this drive is tuned for.

Power Management Features

Real-world client storage workloads leave SSDs idle most of the time, so the active power measurements presented earlier in this review only account for a small part of what determines a drive's suitability for battery-powered use. Especially under light use, the power efficiency of a SSD is determined mostly be how well it can save power when idle.

For many NVMe SSDs, the closely related matter of thermal management can also be important. M.2 SSDs can concentrate a lot of power in a very small space. They may also be used in locations with high ambient temperatures and poor cooling, such as tucked under a GPU on a desktop motherboard, or in a poorly-ventilated notebook.

The S50 Lite supports the most common NVMe power management features, including low-power idle states that are supposed to have quick transition latencies. The maximum power of 9W in the full-power state is a fairly conservative figure; if the drive ever actually draws that much, it's only for very short intervals.

Note that the above tables reflect only the information provided by the drive to the OS. The power and latency numbers are often very conservative estimates, but they are what the OS uses to determine which idle states to use and how long to wait before dropping to a deeper idle state.

Idle Power Measurement

SATA SSDs are tested with SATA link power management disabled to measure their active idle power draw, and with it enabled for the deeper idle power consumption score and the idle wake-up latency test. Our testbed, like any ordinary desktop system, cannot trigger the deepest DevSleep idle state.

Idle power management for NVMe SSDs is far more complicated than for SATA SSDs. NVMe SSDs can support several different idle power states, and through the Autonomous Power State Transition (APST) feature the operating system can set a drive's policy for when to drop down to a lower power state. There is typically a tradeoff in that lower-power states take longer to enter and wake up from, so the choice about what power states to use may differ for desktop and notebooks, and depending on which NVMe driver is in use. Additionally, there are multiple degrees of PCIe link power savings possible through Active State Power Management (APSM).

We report three idle power measurements. Active idle is representative of a typical desktop, where none of the advanced PCIe link or NVMe power saving features are enabled and the drive is immediately ready to process new commands. Our Desktop Idle number represents what can usually be expected from a desktop system that is configured to enable SATA link power management, PCIe ASPM and NVMe APST, but where the lowest PCIe L1.2 link power states are not available. The Laptop Idle number represents the maximum power savings possible with all the NVMe and PCIe power management features in use—usually the default for a battery-powered system but rarely achievable on a desktop even after changing BIOS and OS settings. Since we don't have a way to enable SATA DevSleep on any of our testbeds, SATA drives are omitted from the Laptop Idle charts.

The S50 Lite is one of the more power-hungry drives when idle power management is disabled, drawing over 1W. But the low-power idle states are working well, unlike what we saw with the Intel SSD 670p that uses a close relative of this SM2267 controller. (We're still working with Silicon Motion to figure out that bug.) It also appears that Silicon Motion has moderately improved the real-world wake-up latencies, which are surprisingly high for the SM2262EN drives. The competition shows that there's still room for Silicon Motion to provide an order of magnitude improvement here, and we'd like to see the SMI controllers start living up to the transition times advertised by their firmware.