The Western Digital WD Black SN750 SSD Review: Why Fix What Isn't Broken?
by Billy Tallis on January 18, 2019 8:01 AM ESTAnandTech Storage Bench - The Destroyer
The Destroyer is an extremely long test replicating the access patterns of very IO-intensive desktop usage. A detailed breakdown can be found in this article. Like real-world usage, the drives do get the occasional break that allows for some background garbage collection and flushing caches, but those idle times are limited to 25ms so that it doesn't take all week to run the test. These AnandTech Storage Bench (ATSB) tests do not involve running the actual applications that generated the workloads, so the scores are relatively insensitive to changes in CPU performance and RAM from our new testbed, but the jump to a newer version of Windows and the newer storage drivers can have an impact.
We quantify performance on this test by reporting the drive's average data throughput, the average latency of the I/O operations, and the total energy used by the drive over the course of the test.
The WD Black SN750 improves slightly over its predecessor on The Destroyer, setting a new record for the highest average data rate from a TLC-based SSD.
The SN750 has slightly lower average latency on The Destroyer than its predecessor, but the Phison E12-based Corsair MP510 is in the lead among flash-based SSDs. The MP510 and both the current and previous WD Black are essentially tied for 99th percentile latency.
The SN750 improves on both average read and write latency scores, but the Corsair MP510 has a much better average write latency on The Destroyer than the WD Black or even the Intel Optane 900P.
The 99th percentile read and write latency scores for the SN750 are essentially unchanged from the previous WD Black, leaving it with one of the best QoS scores for reads but a score for writes that is worse than several of last year's TLC-based competitors.
The total energy consumption of the new WD Black over the course of The Destroyer is about 4% lower than its predecessor, further increasing WD's lead in NVMe power efficiency.
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namechamps - Friday, January 18, 2019 - link
Strangely enough I don't think anandtech has ever reviewed the 970 Pro which is likely why it isn't in the comparison. They have done the 960 pro and the 970 evo but not the 970 pro.Ryan Smith - Friday, January 18, 2019 - link
"Whatever happend to the Samsung PRO in those comparisons?"Unfortunately Samsung never sampled the 970 PRO, so we don't have it on hand. And all indications are that they're just about done with it, having never released a 2TB version (like they did the 960 PRO).
I'm really not sure if we're going to see any new consumer MLC drives in 2019. The market has bifurcated into TLC and then more boutique solutions like Z-NAND and 3D XPoint.
althaz - Friday, January 18, 2019 - link
The 512Gb drive is a ~$150 part, just buy it and test it? To many this remains the most prestigious tech site around for at least some things. SSDs have been one of those things. Not having the latest of Samsung's pro drive in your results kinda makes this whole thing not worth it, IMO.If you need an excuse do a "MLC Redux" review where you look at what was probably the faster ever MLC drive and talk about how SSD tech has changed.
eldakka - Friday, January 18, 2019 - link
" just buy it and test it?"I'm sure anandtech would be delighted to test it if you sample one to them, or donate $150 to them to purchase one with.
GreenReaper - Saturday, January 19, 2019 - link
This is the level of a business expense though. Even if you did one a day for every day of the year it would be $53,400. OK, you could get a full-time journalist for that in some places, but that assumes they are kept and not sold on or used for anything else.Solandri - Monday, January 21, 2019 - link
More troubling is that unwillingness to buy a product for review smacks of demanding bribes. "Give us a free sample or we won't review your product." Which implies that companies which shower the reviewer with gifts will get more favorable reviews.Ideally, a review site should *never* accept free samples, and do all their product reviews with samples bought from the store. That's the only way to completely eliminate any undue influence the product manufacturer may have on the product review.
Dark_wizzie - Friday, January 18, 2019 - link
I don't think they actually reviewed the 970 Pro?StevoLincolnite - Saturday, January 19, 2019 - link
Yeah. Comparisons have been a bit crap on Anandtech lately.The RTX 2080 review is lacking a good lineup of GPU's to compare with... Despite promises of "Adding more later". (Never happened sadly.)
joesiv - Friday, January 18, 2019 - link
I would love to see at least some endurance testing in anandtechs reviews. I think it's something that's missing pretty much all SSD testing I see. Yes, speed is great, but endurance is something perspective owners will care more about in the long term.NAND technology is changing over time, is it changing for the better? More layers, but often at the expense of P/E Cycles.
SSD Firmwares as well have gotten both a lot more reliable, but also a lot more complicated, with different companies doing different things to maximize performance and also endurance.
Without testing these things, we don't know if there are duds in terms of firmwares/drives that don't strike a good balance between performance/reliability.
Bare minimimum I would love to see ananadtech do the following:
- Talk to manufacturers about the actual specifications of the NAND, what is the P/E Cycle rating for the NAND. Then list it in the specs for the drives so we can do our own research/homework if we want to. This spec is very often missed in the most marketing material.
- Do a quick capture of the SMART data at the very start of the testing
- Do a capture of the SMART data at the very end of your testing.
- Check out the Block Erase Count specifically. The Average Block Erase count would give a good approximation of how much life you've used just within your benchmark suite. It's much more grainular than Percent Life Used. This SMART attribute can vary between different manufacturer/firmware/controllers, so you might need to contact the manufacturer for this info.
In the end, you'll have something like: Rated P/E count / Average Block Erase, and since your test suite is likely pretty similar between SSD's, it would be a useful metric.
Bonus points, you could also look at NAND writes (not to be confused with Host Writes), during your testing, as it's related to life expectancy and can be corrolated with Total Byte Written.
I wouldn't be surprised to see that some drives write a lot more to NAND than you are expecting, and thus have higher Average Block Erases during your testing.
At my company when I did this test, while we were evaluating a drive for our products, Tier 1 memory manufacturers and their drives, failed bitterly at this endurance test where most did fine. I attribute this to the firmware. Working with the firmware developement team, we determined that the fix would not be feasible in that generation of product, so we had to skip that product.
Specs aren't everything, we need to test it, endurance is an important aspect, and I'd love to see it represented in your reviews.
romrunning - Friday, January 18, 2019 - link
Whom do you consider to be "Tier 1 memory manufacturers" - Samsung or Intel? I can't imagine their products failing endurance tests. Or are you talking about those you would consider to be lower than Samsung - like AData, Team Group, etc. - as a Tier 2 or Tier 3?