The Western Digital WD Blue SN500 SSD Overview: Shifting The Mainstream To NVMe
Western Digital's mainstream drives had been lengthy branded as WD Blue drives, and these had been transferred to SSDs after the acquisition of SanDisk. The primary two generations of WD Blue SSDs had been SATA drives that used TLC NAND, and had been worthy rivals for the Essential MX Sequence and Samsung 850 EVO. The WD Blue SN500 is the third technology of WD Blue SSD and places the WD Blue model in a very completely different market phase: the SN500 is an entry-level M.2 NVMe exhausting drive.
Western Digital has been promoting NVMe dwelling drives for a number of years with its high-end WD Black model. NVMe is now not only for enthusiastic merchandise. Within the final 12 months, we've seen most SSD manufacturers supply low-end NVMe merchandise by way of value and efficiency between their SATA and high-end NVMe choices. This entry-level NVMe area of interest has generally been virtually utterly compressed in high-end, low-cost drives. Nevertheless, the overall concept of dividing the marketplace for shopper NVMe SSDs into two ranges is just not related. SATA is more and more getting used for major storage in shopper PCs. Western Digital supported this development over a 12 months in the past with the PC SN520 SSD for OEMs, from which the WD Blue SN500 is derived.
WD Blue SN500 specs
M.2 2280 One-sided
NVMe PCIe three x2
Western Digital in-house
SanDisk 64-layer 3D TLC
None (host reminiscence buffer is just not supported)
1700 MB / s
1700 MB / s
1300 MB / s
1450 MB / s
four KB Occasional studying
4KB random writing
Though the SN500 is known as WD Blue, it’s not a useful substitute for the SATA WD Blue SSDs. The SATA predecessors supplied capacities of as much as 2 TB, whereas the one capability choices of the SN500 are presently 250 GB and 500 GB. These are the most typical and necessary capability factors for shopper SSDs, however the lack of 1TB and 2TB choices is a blatant failure, particularly now that 1TB drives are near $ 100. The shortage of high-performance variations of the SN500 is smart given the OEM it's based mostly on, the SN520: this drive ought to compete with the smallest kind issue pill PCs and the thinnest notebooks. The OEM SN520 is obtainable in kind components like M.2 2230. Though the usual SN500 makes use of the extra frequent size of 80mm, which affords the widest compatibility with shopper methods, it maintains the identical format that places all of the electronics within the highlight 30mm of the cardboard. The SN500 makes use of a design that was by no means meant for greater than 512 GB of Flash. The additional size on the cardboard is just occupied by the drive label.
Like many entry-level NVMe SSDs, the SN500 makes use of solely two PCIe lanes for its host interface, guaranteeing that the height efficiency of high-end drives with PCIe x4 connections cannot be achieved. The decrease observe depend helps maintain the controller's pin depend and energy consumption low. These are necessary components for a M.2 2230 drive, however a lot much less for a retail drive just like the SN500.
The opposite large trade-off in SN500 design is that it doesn’t embody a DRAM buffer for caching the mapping tables to transform logical block addresses (LBAs) to bodily reminiscence addresses. A DRAM-free SSD often has a a lot decrease efficiency than a mainstream drive with sufficient DRAM to retailer the mapping data for your entire SSD. Within the NVMe world, the Host Reminiscence Buffer characteristic permits SSDs to borrow a small portion of the primary system RAM (sometimes just a few dozen MBs) to compensate for the ability loss that DRAMless SATA drives cannot keep away from. Western Digital determined to not use the Host Reminiscence Buffer (HMB) characteristic for the SN500 and SN520, however determined to put in a few MB of reminiscence into the controller itself, however not near the 256MB or 512MB obtainable on the time Drives with discrete DRAM would include chips.
Other than these two limitations, the SN500 controller has the identical fundamental structure because the WD Black SN750 controller. Western Digital has designed this structure to be scalable to a variety of merchandise. Subsequently, the discount configuration discovered on the SN500 was all the time a part of the plan. That is the primary technology of NVMe's personal controller designs from Western Digital. Nevertheless, our expertise with the WD Blacks doesn’t make it really feel like a 1.zero product: they’ve skipped all of the disappointments that Silicon Movement and Phison had with their first product NVMe controllers and as an alternative the WD Black with NVMe SSDs from Samsung , The WD Blue SN500 is not going to set any efficiency data with only one PCIe x2 interface, nevertheless it has the potential to proceed the spectacular observe file of energy effectivity that Western Digital has constructed.
Though the WD Blue SN500 is considerably low for NVMe requirements, the efficiency specs are nonetheless far past what SATA SSDs can supply. The zero.three SPPD write-through score of the SN500 over a 5-year restricted guarantee is commonplace on mainstream and plenty of high-end SSDs. Present retail costs are about 10-15% larger than the great offers on comparable-capacity SATA SSDs, which is why Western Digital costs solely a small further for NVMe efficiency. There are different DRAM-free NVMe SSDs and a few QLC-based NVMe SSDs available on the market, that are cheaper than the WD Blue SN500. Subsequently, the brand new WD Blue doesn’t simply should surpass SATA to be aggressive.
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