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)
Orange is for the new drives, Blue is for the previous generation models

The burst sequential read speeds of almost all of these SATA drives are essentially equivalent; the slightly lower scores from the new WD and SanDisk drives are not a meaningful drop from the previous generation.

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.

Sustained 128kB Sequential Read

On the longer test of sequential reads, the WD Blue 3D NAND and SanDisk Ultra 3D end up in the second tier of SSDs, tied with the Intel 545s and Toshiba's MLC-based OCZ VX500, but Samsung's 850 PRO and 850 EVO still have a substantial performance advantage.

Sustained 128kB Sequential Read (Power Efficiency)

The power efficiency of the WD Blue 3D NAND and SanDisk Ultra 3D is excellent, trailing behind only the MLC-based OCZ VX500 that also uses a reduced amount of external DRAM. The previous generation of SanDisk and WD drives had the same power efficiency as Samsung's 850 PRO and EVO, which was good by last year's standards.

From QD1 to QD2, the WD Blue 3D NAND and SanDisk Ultra 3D see a slight improvement in sequential read performance and don't benefit any further from higher queue depths. The Samsung 850 PRO and 850 EVO both show a much larger jump in performance from QD1 to QD2, leading to a higher steady-state sequential read speed. The OCZ VX500 can actually match the Samsung drives at high queue depths, but it doesn't saturate until QD4.

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)

As with sequential reads, the burst sequential write speed of the new WD and SanDisk drives is slightly reduced from the preceding generation, but the performance isn't low enough to make the new drives stand out from the crowd.

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

The performance of the WD Blue 3D NAND and SanDisk Ultra 3D on the longer sequential write test is much improved from the previous generation of drives, but still rather slow compared to the competition.

Sustained 128kB Sequential Write (Power Efficiency)

With a substantial performance boost, the power efficiency of the latest WD/SanDisk SSDs is now about average, and is competitive with Samsung's drives but far lower than what the Crucial MX300 or OCZ VX500 offer.

The mediocre sustained sequential write performance of the new WD/SanDisk 3D NAND SSDs is due to a combination of relatively low performance once the drive has reached its full performance, and a slow ramp up that is still not quite at full speed by QD4. Most drives are operating at or very near their full performance at QD2.

Random Performance Mixed Read/Write Performance


View All Comments

  • TheinsanegamerN - Sunday, September 17, 2017 - link

    Talk about mountains and molehills.

    the "performance bottlenecks" of SATA III are only of concern to .01% of buyers. For most tasks, your network interface will be the bottleneck. And when sata IS the bottleneck, the difference between PCIE and SATA are minimal at best.

    As for price, I agree that prices are high, but I also know that, having built multiple SSD machines, you are overblowing the issue. 512GB drives can be had for $100 on sale, and that is more storage then 90% of users need.

    A drive capable of 500MB/s speeds is hardly low performance.
  • Magichands8 - Sunday, September 17, 2017 - link

    Actually SATA bottlenecks should be of concern for anyone who has to wait for their data to be moved, recovered or otherwise accessed. Which can easily happen if anyone transfers anything on the order of a few gigabytes. It's especially concerning when those bottlenecks are imposed by borderline obsolete technology which is absolutely, completely unnecessary. And the response as to why always seems to be "just because" as if in defense of tech companies dragging their asses. One of the reasons why SSDs were adopted as slowly as they were is because most users weren't even aware of the benefits. For people just checking their Facebook and reading e-mails why even care about SATA III? Just stick with SATA I. Or better yet just ignore SSDs all together and stick with spinning rust. Or hell just use a 15 year old computer. Or by a $200 smart phone and bypass computers all together. More and more it's the case that a smartphone is 'good enough' for most people such that more and more of those of us with actual computers are going to run into the limitations of SATA III. There's just no excuse. I'm aware of the better technology which is one of the reasons why I ignore every SSD release like these here with specs no different than any other SSD. Like I said, if someone is in desperate need of a replacement drive it makes some sense but by and large these releases are pointless. Companies SHOULD have an interest in giving us a reason to upgrade, a reason to buy their products. Reply
  • Slaveguy - Thursday, September 14, 2017 - link

    You're crippled by your twisted little kid leg, slave Reply
  • MajGenRelativity - Thursday, September 14, 2017 - link

    What? Reply
  • MrSpadge - Thursday, September 14, 2017 - link

    What's a "wrong" form factor, then? Reply
  • Bullwinkle J Moose - Thursday, September 14, 2017 - link

    " the SanDisk Ultra 3D is a long-overdue replacement for the Ultra II. Both of the new products use the same technology under the hood; they differ primarily in the stickers on the outside of the drive and the retail packaging it arrives in. "

    Yup, those new stickers are long overdue!
  • MajGenRelativity - Thursday, September 14, 2017 - link

    The comment on the same tech is in comparison to the WD Blue 3D. The Ultra 3D is clearly different from the Ultra 2 Reply
  • kmmatney - Thursday, September 14, 2017 - link

    I bought my 1TB Ultra II 3 years ago for $219 - still running great. What is long overdue is lower pricing. Reply
  • ddhelmet - Thursday, September 14, 2017 - link

    Why buy this over 850 EVO for 250 and 500 GB? They're both the same price. Reply
  • MajGenRelativity - Thursday, September 14, 2017 - link

    Higher endurance and lower power consumption are the advantages the article mentions. Reply

Log in

Don't have an account? Sign up now