WD Blue 1 TB NVME Dram?

[Vedant309]

Does the WD Blue NVME have Dram cache in it? To be more specific, this WD Blue NVME: WD Blue™ 3D NAND SATA M.2 2280 SSD

https://www.canadacomputers.com/product_info.php?cPath=179_1927_1928&item_id=114575

[Velcade]

No

[GoldenLag]

8 minutes ago, Vedant309 said:

WD Blue NVME

Thats not the WD blue Nvme, that is the wd blue m.2 sata. not the WD blue sn550 which is Nvme. 

 

https://ca.pcpartpicker.com/product/9vWBD3/kingston-a2000-1-tb-m2-2280-nvme-solid-state-drive-sa2000m81000g

 

This onr is NVMe and has Dram cache. 

[spartaman64]

the wd blue sn550 doesnt have dram but apparently it uses nvme protocol 1.4 which makes up a bit for it

https://www.anandtech.com/show/14543/nvme-14-specification-published

[NewMaxx]

The SN550 lacks DRAM and relies instead on SRAM coupled with some good design decisions.

1. Its controller is a scaled-down version of what's found on the SN750: 4-channel instead of 8 and no DRAM controller. This is a powerful controller.
2. Static SLC. This has higher endurance than dynamic SLC and also means the controller doesn't have to worry about juggling SLC, SLC-TLC conversion, same-zone garbage collection and wear-leveling, etc. Static SLC is dedicated and has its own zone. This makes for very consistent performance even when fuller and faster direct-to-TLC speeds than you'll find on any other budget NVMe drive.
3. 850+ MB/s in TLC mode at 1TB. It also uses BiCS4/96L flash so has good all-around performance including very fast reads for a 4-channel drive even at the smallest capacity.
4. WD has a decent amount of dedicated SRAM which is a tactic found on some other DRAM-less drives (e.g. Phison S11). SRAM is faster than DRAM and HMB, just limited in size.
5. WD has several patented techniques to make the most of this SRAM. Some are pretty obvious, such as address compression: in simplified terms, if you're pulling data that's sequential you can point to the initial address plus a finite number of adjacent offsets such that the overall "chunk" is much larger for address space. Another technique would be segmentation and asynchronous I/O, that is being selective in page latency (for example) based on workload to minimize downtime.
6. The NVMe protocol is simply superior to AHCI anyway so comparing directly to a SATA drive doesn't make a ton of sense.

Unfortunately, the crowds that go "DRAM or bust!" on one side or "DRAM-less is fine for average user" are both wrong. The reason is that design principles usually follow, in other words a drive manufacturer that's making a budget drive and leaving out DRAM is also likely to go with a large, dynamic SLC cache which will exacerbate the problem when the drive is fuller. They'll use a weaker controller. Etc. So saying "DRAM-less" doesn't make any sense by itself, you have the take the drive as a whole.

 

With that understanding in mind, having fast flash partnered with a conservative SLC cache design means you don't see those shortfalls much. Add in a powerful controller with some clever techniques and a large SRAM cache, and you have a pretty decent budget drive, particularly if you can improve latency and efficiency with the NVMe protocol.