Mixed Random Performance

Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.

Mixed 4kB Random Read/Write

The mixed random I/O performance of the Intel SSD 660p is clearly above the other low-end NVMe drives we've tested, or the Crucial MX500 SATA drive. It scores closer to a mid-range NVMe SSD. After filling the drive, performance is cut in half, leaving it performing near low-end NVMe drives like the Phison E8-based Kingston A1000 and below the MX500.

Sustained 4kB Mixed Random Read/Write (Power Efficiency)
Power Efficiency in MB/s/W Average Power in W

The power efficiency of the 660p during the mixed random I/O test is unimpressive but doesn't stand out as being significantly worse that other low-end NVMe drives even when the test is run on a full drive.

The Intel SSD 660p shows very slow performance growth throughout most of the test, but it picks up speed reasonably well toward the end as the workload shifts toward pure writes, and the SLC cache handles things well. When the drive is full, the reduced capacity of the SLC cache prevents speed from increasing much.

Mixed Sequential Performance

Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.

Mixed 128kB Sequential Read/Write

The Intel SSD 660p performs better than other entry-level NVMe SSDs or SATA drives when the mixed sequential I/O test is run on a mostly empty drive with a large SLC cache. After the drive is filled, performance drops down to slightly ahead of the 600p and Crucial MX500.

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

The power efficiency of the Intel SSD 660p during the mixed sequential I/O test is decent when operating entirely out of the SLC cache, and on par with most other low-end NVMe drives when the 660p is full.

When the test is run on a mostly-empty 660p the performance shows a very typical bathtub curve and no sign of the SLC cache running out. When the drive is full, performance decreases steadily as the proportion of writes increases.

Sequential Performance Power Management
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  • eastcoast_pete - Tuesday, August 7, 2018 - link

    Firstly, thanks for calling me one of the "idiots salivating over elusive real world endurance rating numbers". I guess it takes one to know one, or think you found one. Second, I am quite aware of the need to have a sufficient sample size to make any inference to the real world. And third, I asked the question because this is new NAND tech (QLC), and I believe it doesn't hurt to put the test sample that the manufacturer sends through its paces for a while, because if that shows any sign of performance deterioration after a week or so of intense use, it doesn't bode well for the maturity of the tech and/or the in-house QC.
    And, your last comment about your 80 GB near first gen drive shows your own ignorance. Most/maybe all of those early SSDs were SLC NAND, and came with large overprovisioning, and yes, they are very hard to kill. This new QLC technology is, well, new, so yes I would like to see some stress testing done, just to see if the assumption that it's all just fine holds, at least for the drive the manufacturer provided.
    Reply
  • Oxford Guy - Tuesday, August 7, 2018 - link

    If a product ships with a defect that is shared by all of its kind then only one unit is needed to expose it. Reply
  • mapesdhs - Wednesday, August 8, 2018 - link

    Proof by negation, good point. :) Reply
  • Spunjji - Wednesday, August 8, 2018 - link

    That's a big if, though. If say 80% of them do and Anandtech gets the one that doesn't, then...

    2nd gen OCZ Sandforce drives were well reviewed when they first came out.
    Reply
  • Oxford Guy - Friday, August 10, 2018 - link

    "2nd gen OCZ Sandforce drives were well reviewed when they first came out."

    That's because OCZ pulled a bait and switch, switching from 32-bit NAND, which the controller was designed for, to 64-bit NAND. The 240 GB model with 64-bit NAND, in particular, had terrible bricking problems.

    Beyond that, there should have been pressure on Sandforce's decision to brick SSDs "to protect their firmware IP" rather than putting users' data first. Even prior to the severe reliability problems being exposed, that should have been looked at. But, there is generally so much passivity and deference in the tech press.
    Reply
  • Oxford Guy - Friday, August 10, 2018 - link

    This example shows why it's important for the tech press to not merely evaluate the stuff they're given but go out and get products later, after the initial review cycle. It's very interesting to see the stealth downgrades that happen.

    The Lenovo S-10 netbook was praised by reviewers for having a matte screen. The matte screen, though, was replaced by a cheaper-to-make glossy later. Did Lenovo call the machine with a glossy screen the S-11? Nope!

    Sapphire, I just discovered, got lots of reviewer hype for its vapor chamber Vega cooler, only to replace the models with those. The difference? The ones with the vapor chamber are, so conveniently, "limited edition". Yet, people have found that the messaging about the difference has been far from clear, not just on Sapphire's website but also on some review sites. It's very convenient to pull this kind of bait and switch. Send reviewers a better product then sell customers something that seems exactly the same but which is clearly inferior.
    Reply
  • southleft - Tuesday, May 14, 2019 - link

    SSDs replaced under warranty by the maker can sometimes have a silver lining, so to speak. Some years ago we had an Intel X25 80GB fail. Intel replaced it with a newer model 320 which was basically the same but updated to SATA III. We also had a Sandisk Ultra 120GB fail, and Sandisk replaced it with an Ultra 2. These newer replacement models are still running OK some 6 years later, for what it's worth! Reply
  • chrcoluk - Wednesday, September 25, 2019 - link

    I agree, this is more important than hitting embargo date for publishing.

    Its the content not the date that matters. If it takes a year to do it, then so be it. I never buy hardware on release date, to me that's just stupid.
    Reply
  • Oxford Guy - Tuesday, August 7, 2018 - link

    People trusted Samsung with the 840 and then, oops...

    The real rule is verify then trust.
    Reply
  • mapesdhs - Wednesday, August 8, 2018 - link

    One thing about the 840 EVO issue which was a real pain was trying to find out if the same thing affected the standard 840. In the end my conclusion was yes, but few sites bothered to mention it. Oddly enough, of the many SSDs I have, one of the very few that did die was a standard 840. I never bought an 840 EVO because of the reports that came out, but I have a fair few 840 Pros and a heck of a lot of OCZs. Reply

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