The Western Digital WD Blue SN500 SSD Review: Moving The Mainstream To NVMe
by Billy Tallis on April 19, 2019 9:30 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 average data rate of the WD Blue SN500 on The Destroyer puts it in a tie with the ADATA SX8200 and ahead of other entry-level NVMe drives. The 250GB SN500 outperforms even the 1TB SATA WD Blue SSD and the 1TB QLC-based Intel 660p. Samsung's 970 EVO Plus is significantly faster overall, but that's to be expected considering there is no more high-end option in this capacity class.
The great average and 99th percentile latency scores from the WD Blue SN500 on The Destroyer make it easy to forget that the SN500 is designed to be an entry-level NVMe drive, not a flagship high-end product (to the extent that such a thing is possible with TLC NAND in such small quantities).
The average read latency of the WD Blue SN500 on The Destroyer is faster than any other drive in its capacity class, and only 60% slower than the Intel Optane 800p. The average write latency doesn't stand out much from the competition, but the SN500 is still behaving more like a high-end drive rather than showing any of the acute weaknesses often found in entry-level products.
The 99th percentile read and write latency scores from the SN500 are similarly excellent, and better than can reasonably be expected from a DRAMless SSD that we know is doing a lot of background garbage collection during this test.
The WD Blue SN500 was quite power efficient during The Destroyer; despite being significantly slower overall than the WD Black SN750, the SN500 used a bit less energy in total. The other drives in its capacity class all used at least 50% more energy to complete this test, and the Toshiba RC100 despite seeming most similar at a high level (DRAMless, TLC, NVMe) took several times longer to run the test and used several times the energy.
Facebook
Twitter
RSS
50 Comments
View All Comments
DyneCorp - Sunday, April 21, 2019 - link
You got the EX920 512GB on sale. That's not the typical retail price, and the SN500 is already sitting at $65 retail.You understand the price of this drive will go down? As they always do after initial release? And when the prices of NAND skyrocket again, the SN500 will have a major advantage?
For the majority of consumers, the SN500 is a viable option.
airider - Friday, April 19, 2019 - link
This is WD clearing out their inventory while making way for the higher capacity/performance versions coming out shortly. Don't expect to see this product anymore by the end of 2019.flyingpants265 - Saturday, April 20, 2019 - link
Wait, so it's not QLC nand? That's great. It states 300TB write endurance, compared to the 100TB of the 500gb Crucial P1, for the same price. Goodbye, QLC! For now..DyneCorp - Sunday, April 21, 2019 - link
For consumers, the endurance rating matters none. You'll never chew through 100TB of endurance, especially under consumer workloads. The massive SLC cache buffers utilized in the P1 and 660p in addition to smart caching algorithms increase endurance substantially. Also, the DRAM buffer in addition to smart controller firmware effectively mitigate write amplification by several factors. You'll never chew through the endurance of the P1 or the 660p, period.Endurance ratings are meaningless under consumer workloads. SSDs far outlast their given endurance ratings.
flyingpants265 - Wednesday, April 24, 2019 - link
Well, hopefully. Because just to download install one game (hitman 2) requires about 240GB of writes. If I do that 3 times, that's 1% of my drive's life gone.flyingpants265 - Wednesday, April 24, 2019 - link
Uh, 4 times.DyneCorp - Wednesday, April 24, 2019 - link
This is incorrect. 240GB of writes does not equal 240GB of endurance lost, especially if they are sequential writes because:1.) The controller can reduce write amplification by intelligently shifting data around
2.) Sequential writes to the SLC cache increase endurance significantly
3.) Folding blocks from the pSLC cache to QLC actually increases endurance
DyneCorp - Wednesday, April 24, 2019 - link
By the way, this is evidenced by the ADATA SU800. It has a massive dynamic SLC cache buffer and older Micron 32-layer 384-Gbit NAND and still carries the highest endurance rating on the market.willis936 - Saturday, April 20, 2019 - link
I'm surprised there isn't a significant difference in idle power consumption or drive-side efficiency for a DRAMless NVMe drive. This is a pretty nice piece of hardware, regardless of price.DyneCorp - Saturday, April 20, 2019 - link
Thanks for the review, Billy! I really appreciate your work; you always do an excellent job and I appreciate you taking time out of your life to throw these reviews up.Without the DRAM buffer, how do you think write amplification is affected? Obviously endurance is actually quite high (in SU800 territory) and performance is quite high. This is especially interesting considering how small the SLC cache buffer is.
Do you think WD has effectively mitigated negative endurance impact through firmware?