Comparisons & Benchmarks
The SATA SSD market hasn't been very exciting lately. Samsung released the 850 EVO in a wide range of capacities that scale all the way up to 4TB. In the interim, only a very few SSDs have matched the EVO's performance, features, and pricing. The Sk Hynix SL308, and soon the SC308, are the most notable. The Adata XPG SX950 looks to join those ranks with a combination of 3D NAND and firmware tuned to deliver a high-performance user experience.
We've included the notable SSDs in our review and added the Crucial MX300, also with Micron 3D NAND, and the Intel SSD 540s. The Mushkin Triactor and OCZ Trion 150 fill in the gaps, but, like the MX300 and 540s, don't deliver on the same level as the product from South Korea.
Sequential Read Performance
All of the devices deliver exceptional sequential read performance. This is the easiest workload for storage devices. Gamers looking for fast load times can gauge performance with this chart. The differences between products are minimal. That's why many people say SATA SSDs all perform about the same.
Sequential Write Performance
You can see the difference if you challenge the SSDs with more complex workloads. The Adata XPG SX950 uses MLC flash, so we don't have to worry about a large sequential write drop-off like TLC-based products. We confirmed the steady performance with HD Tune Pro by applying a sequential write workload across the entire LBA range.
Random Read Performance
Random workloads expose the most performance variation. Random read performance is one of the most important aspects of the four-corner measurements because it directly relates to the user experience. Flash is so fast that the queue depth rarely reaches more than three or four, but your PC contently reads and writes small random files to log data and launch applications. We like to see queue depth (QD) 1 random read performance north of 10,000 IOPS, but it's difficult to achieve. Even new NVMe SSDs have a difficult time reaching that high mark. The SX950 doesn't reach it either, but it does perform well for a mainstream SSD.
Random Write Performance
The Adata XPG SX950 delivered really odd random write performance during our automated test. We think the plastic case traps heat and promotes thermal throttling during extended heavy workloads. A metal case would help dissipate the heat instead of serving as insulation.
80% Mixed Sequential Workload
The XPG SX950's mixed workload performance is one of the best results we've measured for a SATA SSD. The SX950 delivers very high performance even at QD2 (the SSD doesn't process reads and writes simultaneously at QD1).
80% Mixed Random Workload
The SX950's mixed random performance is also stellar. The drive matches the Crucial MX300 but fails to match the high marks set by the Samsung 850 EVO.
Even with MLC flash and a new Intelligent SLC algorithm, the SX950 still suffers during sequential steady-state conditions. The drive delivers TLC-like performance with a pure sequential write workload. The drive uses overprovisioning to combat steady-state conditions even when you fill up the drive with data, but you shouldn't experience this condition during normal use.
The 80% (normal use) and 70% (workstation use) mixtures show strong performance, but adding more writes to the workload penalizes the SX950.
The SX950 delivers roughly 5,000 IOPS during this steady-state test, with some deep peaks and valleys in the measurement. The SX950 isn't as consistent as some of the premium SATA SSDs (Samsung 850 Pro, SanDisk Extreme Pro, Intel SSD 730), but those products cost much more and are difficult to find due to their age.
PCMark 8 Real-World Software Performance
For details on our real-world software performance testing, please click here.
The Adata XPG SX950 tries to outpace the other SATA SSDs, and it comes very close in many of the application tests. It's been a long time since Adata held a performance crown, but this SSD comes close. The SX950 even matches the 850 EVO in many workloads.
Application Storage Bandwidth
The SX950 is close to the mighty 850 EVO. In applications that matter, the SX950 delivers very high performance compared to other SATA SSDs. It even outperforms many of the popular SSDs.
PCMark 8 Advanced Workload Performance
To learn how we test advanced workload performance, please click here.
The PCMark 8 Extended Storage Test shows us that the SX950 works well under very heavy workloads. This stems from using MLC flash instead of TLC, but we expected a better recovery score. During the recovery phase of the test, the drives receive 5 minutes periods of idle time to process background activities. The controller manages the data movement during background processes, such as garbage collection and wear leveling. Just like your host processor, the SSD controller has limited resources and clock cycles. When you read or write to the drive during background activity, performance suffers as the processor tries to multitask.
Total Service Time
The Adata XPG SX950 falls into the top tier (lower is better) during the service time test. It matches many of the other products during heavy use but falls deeper into the pack of SSDs during recovery.
Disk Busy Time
We often use the disk busy time test to predict power consumption in real world conditions, but that isn't the case with the SX950, as we'll see shortly. The SX950 cuts through the workloads and quickly returns to an idle state.
The BAPCo SYSmark SE system test includes a new responsiveness test. System responsiveness is closely associated with disk performance, but other factors play a role. We use a Lenovo Y700-17 gaming notebook to run these tests. The SX950's responsiveness score is high, but the power consumption report also gives us an early indicator that the drive uses a lot of power to achieve the result.
Notebook Battery Life
It's often difficult for users to quantify exactly how a single component can affect battery life. High power consumption taxes the notebook battery and limits your power-on time between trips to the wall. The BAPCo MobileMark 2014.5 test makes it easy to compare components. The Sk Hynix SL208 delivers nearly two additional hours of battery life compared to the SX950 480GB. The XPG SX950 isn't a good choice for notebook users that spend a lot of time on battery power.
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