The Western Digital WD Blue SN500 SSD Review: Moving The Mainstream To NVMeby Billy Tallis on April 19, 2019 9:30 AM EST
Western Digital's mainstream consumer drives have long been branded as WD Blue drives, and this carried over to SSDs after their acquisition of SanDisk. The first two generations of WD Blue SSDs were SATA drives using TLC NAND and were worthy competitors for the Crucial MX series and Samsung 850 EVO. The WD Blue SN500 is the third generation WD Blue SSD, and it moves the WD Blue brand over to a very different market segment: the SN500 is an entry-level M.2 NVMe drive.
Western Digital has been selling consumer NVMe drives for a few years using their high-end WD Black branding, but NVMe isn't just for enthusiast products any more. For the past year we've been seeing most SSD brands offering a lower tier of NVMe products that sit between their SATA and high-end NVMe offerings, both in terms of price and performance. This entry-level NVMe niche has at times been squeezed down to almost nothing when there are particularly well-priced high-end drives, but the general idea of splitting the consumer NVMe SSD market into two tiers isn't going away. SATA is starting to be phased out of use for primary storage in client PCs. Western Digital started supporting that trend over a year ago with the PC SN520 SSD for OEMs, which the WD Blue SN500 is derived from.
|WD Blue SN500 Specifications|
|Capacity||250 GB||500 GB|
|Form Factor||M.2 2280 Single-Sided|
|Interface||NVMe PCIe 3 x2|
|Controller||Western Digital in-house|
|NAND||SanDisk 64-layer 3D TLC|
|DRAM||None (Host Memory Buffer not supported)|
|Sequential Read||1700 MB/s||1700 MB/s|
|Sequential Write||1300 MB/s||1450 MB/s|
|4KB Random Read||210k IOPS||275k IOPS|
|4KB Random Write||170k IOPS||300k IOPS|
|Power||Peak (10µs)||5.94 W||5.94 W|
|PS3 Idle||25 mW||25 mW|
|PS4 Idle||2.5 mW||2.5 mW|
|Current Retail Price||$52.99
Despite bearing the WD Blue name, the SN500 is functionally not a direct replacement for the SATA WD Blue SSDs. The SATA predecessors offered capacities up to 2TB, while the SN500's only capacity options are currently 250GB and 500GB. Those are the most common and important capacity points for consumer SSDs, but the absence of 1TB and 2TB options are a glaring omission, especially now that 1TB drives are approaching $100. The lack of high-capacity versions of the SN500 make sense when considering the OEM SN520 it is based on: that drive was intended to compete against the smallest form factor SSDs used tablets and the thinnest notebooks. The OEM SN520 is available in form factors as small as M.2 2230, and even though the retail SN500 uses the more typical 80mm length that offers the broadest compatibility with consumer systems, it retains the same layout that puts all the electronics in the first 30mm of the card. The SN500 uses a design that was never intended to accommodate more than 512GB of flash. The extra length on the card is occupied only by the drive's label.
Like many entry-level NVMe SSDs the SN500 uses only two PCIe lanes for its host interface, which ensures it cannot match the peak performance of high-end drives with PCIe x4 connections. The lower lane count helps keep the pin count and power consumption of the controller down, which are important factors for a M.2 2230 drive but matter considerably less for a retail drive like the SN500.
The other major compromise in the SN500's design is that it does not feature a DRAM buffer for caching the mapping tables for translating logical block addresses (LBAs) into physical memory addresses. A DRAMless SSD usually has significantly lower performance than a mainstream drive with enough DRAM to store the mapping information for the entire SSD. In the NVMe world, the Host Memory Buffer feature allows SSDs to borrow a small amount of the main system RAM (usually a few tens of MB) for this purpose, offsetting the performance loss that DRAMless SATA drives cannot avoid. Western Digital chose not to use the Host Memory Buffer (HMB) feature for the SN500 and SN520, instead opting to include a few MB of memory in the controller itself, but nowhere near the 256MB or 512MB that would be included on drives with discrete DRAM chips.
Aside from those two limitations, the SN500's controller shares the same basic architecture that the WD Black SN750's controller uses. Western Digital designed this architecture to scale across a wide range of products, so the cut-down configuration we find on the SN500 was part of the plan all along. These are the first generation of in-house NVMe controller designs from Western Digital, but based on our experience with the WD Blacks it doesn't feel like a 1.0 product: they skipped over all the disappointments that Silicon Motion and Phison had with their first NVMe controllers, and instead the WD Black went toe to toe with Samsung's NVMe SSDs. The WD Blue SN500 won't be setting any performance records with just a PCIe x2 interface, but it does have the opportunity to continue the impressive track record on power efficiency that Western Digital has been building.
The WD Blue SN500 may be a bit low-end by NVMe standards, but its performance specifications are still far above what SATA SSDs can provide. The SN500's write endurance rating of 0.3 DWPD over a 5-year warranty is standard for mainstream and many high-end SSDs. The current retail pricing is about 10-15% higher than the good deals on mainstream SATA SSDs of comparable capacity, so Western Digital is only charging a small premium for delivering NVMe performance. There are other DRAMless NVMe SSDs and some QLC-based NVMe SSDs on the market that are cheaper than the WD Blue SN500, so the new WD Blue has to do more than just outperform SATA in order to be competitive.
|AnandTech 2018 Consumer SSD Testbed|
|CPU||Intel Xeon E3 1240 v5|
|Motherboard||ASRock Fatal1ty E3V5 Performance Gaming/OC|
|Memory||4x 8GB G.SKILL Ripjaws DDR4-2400 CL15|
|Graphics||AMD Radeon HD 5450, 1920x1200@60Hz|
|Software||Windows 10 x64, version 1709|
|Linux kernel version 4.14, fio version 3.6|
|Spectre/Meltdown microcode and OS patches current as of May 2018|
- Thanks to Intel for the Xeon E3 1240 v5 CPU
- Thanks to ASRock for the E3V5 Performance Gaming/OC
- Thanks to G.SKILL for the Ripjaws DDR4-2400 RAM
- Thanks to Corsair for the RM750 power supply, Carbide 200R case, and Hydro H60 CPU cooler
- Thanks to Quarch for the XLC Programmable Power Module and accessories
- Thanks to StarTech for providing a RK2236BKF 22U rack cabinet.
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Marlin1975 - Friday, April 19, 2019 - linkActually not bad for one that does not have any large external buffer. That and this is the 250gb model so the 500 should perform a little better as well.
Dragonstongue - Friday, April 19, 2019 - link970 Evo Plus quite stands out for NVME based drives at ~$35 more for same size (just did a price check, amazon, 500gb for this vs 970 evo plus)
so while "on paper" this appears great price, is still in very tough ground with ample contendors such as crucial with their p3 ( I believe it was called) countless samsung entries and the like.
for an extra ~$30-$40 seems like "normally" is just not worth it when can do for ones self (such as clock up the slower product, tweaking voltages and the like) when it comes to a "paper" difference and more or less proven real world data this is not all that good a price.
IMO is we take even a high performance HDD as a regular car speed, sata ssd (even highest performance) still is like an expensive supercar speed difference, the next jump would be the nvme based ones which are like top fuel dragsters (at best) but few tracks let them breathe proper and have to deal with engine problems (throttling etc) that normal drive do not have to deal with AND more $$$$$$..
top fuel costs $$$$, do you ALWAYS see this speed, nope, but when you do, is wonderful, when you do not, it becomes a "so why did I pay that much more for little gain and loss in capacity as well as specific motherboards to tap the advantage" etc etc.
kudos to WD, but alas, the margins are so very narrow and expected performance so high is near a non starter for all companies.
I feel the "new standard" for storage should be @500gb for performance and capacity reasons with 1tb prefered (even a 250nvme + whatever size SSD flash in a raid internal no driver required fashion .. I always liked concept of hybrid drives, why not use hybrid memory styles to leverage as well, instead of saddling fast memory with spinning rust, use high speed low endurance flash with lower speed high endurance other flash.
they do pci-e basd, nvme based, sata based etc etc, all have own benefit and detriment. I personally love sata based, leave the motherboard real estate for other things, they should do a further rendition of sata for the hole outs (like me and others whom have a variety of reasons)
if they can patch pci-e to nvme, why not use sta 6 (like current) but tap x2 or x4 pci-e lanes to it as well, let us call it SATA-X, backwarrds compatible with Sta 6g to sata 1 ofc, this would allow some sata or whatever drives up their speed but use a familiar/durable/more widespread form factor.
if all nvme based drives would work in all board or they would not interfere with mobo, not have throttle issues because of dog meta cooling designs (motherboard AND drive maker often enough) it would not be as much an issue, I like sata drive for such reasons, mainly can look "nicer" tend to be much more durable, that much less costly etc etc.
anyways, if WD could do 500 for the price of the 250, that would be most excellent, but as the pricing is, mehhh, overall nice rounded performance with no real shortcomings compared to many others even some of the much more $ drives are not as "rounded" for this they at least did very well at, that much should be said.
like Crucial with MX100, MX500, Samsung with the 800 through 970s (sata and nvme ofc) there are levels that are nice to hit, this SN500 is very much on that edge, up the performance a tough more, reduce price a touch (keep say $40 or better gap between this and the 970 evo plus) then this is that new "leg"
crucial 100/mx500 are more "budget" compared to the "sometimes" faster sammy 8xx/9xx drives, sammy ofc got the speed and endurance markers out there, this "could be" that leg of "rounded performance" just like the mx500 or sammy 8xx/9xx evo ^.^
sonny73n - Saturday, April 20, 2019 - linkIs this a comment or an essay?
Hul8 - Saturday, April 20, 2019 - link"Stream of consciousness" is a style, but usually only applied to fiction.
LMonty - Sunday, April 21, 2019 - linkHaha! He just needed to get it out of his system :)
Thud2 - Saturday, April 20, 2019 - linkCan you elaborate?
Jorgp2 - Sunday, April 21, 2019 - linkPretty sure this is targeted mostly at OEMs
DyneCorp - Wednesday, April 24, 2019 - linkThe MX500 is on par with the 860 EVO. SSDs with Micron 64-layer 3D TLC NAND and the SM2262 controller (HP EX920 and ADATA SX8200) absolutely destroy Samsung 9 series NVMe SSDs in certain metrics.
The initial price of any product is always high. The SN500 will drop in price. In fact, its not even selling at its suggested retail price from most retailers.
And by the way, comparing SSDs to motor vehicles is ridiculous. Please stop.
jabber - Friday, April 19, 2019 - linkIt will do fine for a Steam drive.
fazalmajid - Friday, April 19, 2019 - linkI don’t see how such puny capacities can be mainstream, specially when most motherboards or laptops have a limited number of M.2 slots. My minimum would be a 1TB or 2TB Intel 660P.