Sequential Read Performance

Our first test of sequential read performance uses short bursts of 128MB, issued as 128kB operations with no queuing. The test averages performance across eight bursts for a total of 1GB of data transferred from a drive containing 16GB of data. Between each burst the drive is given enough idle time to keep the overall duty cycle at 20%.

Burst 128kB Sequential Read (Queue Depth 1)

The Mushkin Source turns in respectable performance on the burst sequential read test, and the DRAMless design is clearly not a handicap at all for this workload.

Our test of sustained sequential reads uses queue depths from 1 to 32, with the performance and power scores computed as the average of QD1, QD2 and QD4. Each queue depth is tested for up to one minute or 32GB transferred, from a drive containing 64GB of data. This test is run twice: once with the drive prepared by sequentially writing the test data, and again after the random write test has mixed things up, causing fragmentation inside the SSD that isn't visible to the OS. These two scores represent the two extremes of how the drive would perform under real-world usage, where wear leveling and modifications to some existing data will create some internal fragmentation that degrades performance, but usually not to the extent shown here.

Sustained 128kB Sequential Read

On the longer sequential read test, the Mushkin Source maintains high performance both for the initial test run reading back data that was written sequentially, and when reading from a dataset that was fragmented by the random write tests.

Sustained 128kB Sequential Read (Power Efficiency)
Power Efficiency in MB/s/W Average Power in W

With sequential read performance that is competitive against mainstream drives and a slight power consumption advantage from not having to power DRAM, the Mushkin Source turns in very good power efficiency scores, though not quite as high as the HP S700 managed.

Like any SATA SSD, the Mushkin Source can't quite saturate the SATA interface at QD1. At any higher queue depth, the Source delivers steady full-speed sequential reads.

While the random access performance and power consumption of the Mushkin Source may not have looked good in the broader picture, for sequential reads the Mushkin Source is clearly as fast as any other SATA drive and draws less power than almost any other.

Sequential Write Performance

Our test of sequential write burst performance is structured identically to the sequential read burst performance test save for the direction of the data transfer. Each burst writes 128MB as 128kB operations issued at QD1, for a total of 1GB of data written to a drive containing 16GB of data.

Burst 128kB Sequential Write (Queue Depth 1)

The burst sequential write performance of the Mushkin Source isn't quite top-tier, but it is comparable to most mainstream SATA SSDs.

Our test of sustained sequential writes is structured identically to our sustained sequential read test, save for the direction of the data transfers. Queue depths range from 1 to 32 and each queue depth is tested for up to one minute or 32GB, followed by up to one minute of idle time for the drive to cool off and perform garbage collection. The test is confined to a 64GB span of the drive.

Sustained 128kB Sequential Write

On the longer sequential write test, the Mushkin Source's standing falls somewhat, but it still offers decent performance, unlike the Toshiba TR200.

Sustained 128kB Sequential Write (Power Efficiency)
Power Efficiency in MB/s/W Average Power in W

Every other SATA SSD in this batch uses at least as much power during this test as the Mushkin Source, which easily tops the efficiency ranking.

The Mushkin Source doesn't reach its full sequential write speed until QD4, which is later than some drives but not uncommon even among mainstream SATA SSDs. The Source maintains that performance through the remainder of the test, with no sign of the SLC cache overflowing.

The Mushkin Source may not quite reach the highest sequential write speeds possible for a SATA SSD, but it gets pretty close and is obviously the most efficient SATA drive we've put through this test. That's a strange win, but we'll take it.

Random Performance Mixed Read/Write Performance
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  • Amandtec - Wednesday, November 21, 2018 - link

    On PC Partpicker you can chose a chinese brand 500GB for about $42 vs about $72 for the Samnsung. So it is a little more than 10% difference.
  • piroroadkill - Wednesday, November 28, 2018 - link

    So $30 to not lose your data? Sounds like a good deal.
  • piroroadkill - Wednesday, November 28, 2018 - link

    Yeah, the SSD market is filled with wrong decisions.
    I just basically go for a TLC Samsung drive that fits the budget, and pretty much ignore everything else.
  • kmmatney - Wednesday, November 21, 2018 - link

    Microcenter has their Inland 480GB SSD for $59.99. I have bought about 10 of the Inland SSDs so far, in various sizes (mostly the 240GB for $33). They have all worked great for normal everyday workloads, and most of these were installed as boot drives. The Microcenter SSDs are also DRAMless - maybe they don't bench as well, but they still have that SSD feel to them, and perform well doing normal tasks.
  • fmcjw - Wednesday, November 21, 2018 - link

    Well written article, thorough but not verbose, thank you Billy! Reminds me of Anand and Bruce...
    Recently bought a 480GB no name SSD that uses the same controller and NAND for only around $40 (singles day deal here in my home market in Taiwan). It has similar characteristics to the Source as you described (full disk SLC cache, etc.), but returned it because it makes a loud/hi-freq electrical noise when written to and read from. Forums here say that the 2258XT (or its ASMedia licensed copy) can overheat under heavy use and die before the NAND expires, so thermal design and general electrical design/component quality is critical. I'm not sure if you examined these design flaws or if you plan to add them to future routines? Granted it's probably specific to each production batch, but might be worth checking on each drive that you come across if it's not too much work.

    I understand you include links to Destroyer methodology, but it will be helpful to briefly describe what constitutes a "full" and "empty" drive in brief, for faster reading without having to click through.

    Also, a bit curious about SLC caching, its different types and what that means for real world usage. I imagine frequently accessed operating system files should be kept in SLC, and not moved into TLC, but unsure if any firmware is so smart about this. If if keeps moving files without discretion it will also be bad for write amplification.

    Thanks again!
  • Billy Tallis - Thursday, November 22, 2018 - link

    I hadn't heard about 2258XT controllers dying or overheating. It hasn't happened to any of my drive samples yet. I also don't recall hearing coil whine coming off the Source, though I have heard it from a few SSDs during testing.

    For the full-drive ATSB Heavy and Light test runs, the drive is filled with sequential writes of random data to every single sector, then given a five minute break to cool off and flush caches before the test begins.

    TLC drives generally treat the SLC cache as a write buffer, and will aggressively migrate data from SLC to TLC blocks during idle times. The QLC drives on the market so far are much more willing to keep data in SLC until it is necessary to compact it into QLC blocks, so the SLC cache helps with write and read performance. I'm not aware of any drives that move frequently-read data from TLC/QLC blocks back to SLC to optimize read performance.
  • gglaw - Saturday, November 24, 2018 - link

    Billy - I don't get the indications of when the performance falls off after the SLC cache is full. The graphs indicate it drops off after around 170GB of data is written. How is this possible on a budget TLC drive? Does this mean there is 170GB of SLC cache on this drive? That couldn't be true for a budget DRAM-Less drive since it would add way much to the cost of the drive that the market it is targetting would not need. No one buying this type of drive would be doing workloads to push it past this threshold so it makes 0 business sense to equip it in this way. Basically no performance sense either since this large of a cache will never be used by customers buying bottom barrel drives.

    I'm probably reading it entirely wrong - do you have a clearer explanation of what is going on?
  • Billy Tallis - Saturday, November 24, 2018 - link

    The full-drive sequential write test is essentially a best-case scenario that illustrates the maximum possible SLC cache size for drives with variable-size caches. The drive starts out empty so the SLC cache is at its largest size, and sequential writes are easier for the controller to handle than random writes.

    It looks like the Mushkin Source more or less runs all of its NAND as SLC initially, which is why it takes so long for the write speed to drop. It's also possible that the write throughput from the controller to the NAND is significantly faster than the SATA link, so the drive might have some slack to start folding data from SLC to TLC blocks in the background before the cache fills up.

    The other SM2258 drives appear to start folding before the cache is full, but with the slower 32L TLC that did have an impact on the write speed.

    At some point I may expand the SLC cache test to better show the range of behaviors for variable-size caches.
  • WasHopingForAnHonestReview - Thursday, November 22, 2018 - link

    Great review, thank you.
  • excelle08 - Thursday, November 22, 2018 - link

    This could benefit for non-power user consumers who just want faster booting or everyday software loading. However the price is not reasonable for such a piece of junk - Intel's 660p already sucks, let alone this unknown brand who is likely to use "who knows" black/white flash chips, plus without DRAM cache. If I only have $30 budget for storage I'd rather go to ebay and search for a used older SATA2 MLC stuff(such as Intel X-25M) than this 120G QLC drive.

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