Help! Test! Please!

[chan_QAQ]

In China, Western Digital's SN550 1TB, produced in July with firmware number 23XXXXWD, reduced the out-of-cache writes from 800MB/s to 400MB/s with no announcement notice and no change in selling price, which could not be detected without testing. After testing, past products with firmware version 21XXXXWD, the firmware could not be updated to 23XXXXWD, most likely Western Digital made changes at the hardware level. Western Digital has also secretly switched Red NAS Hard Drives from CMR to SMR before, so can you test to see if there are any such products outside of China? If so, you can prevent Western Digital from harming consumers.

[Wooden Law - Black]

This was explained in a Chinese video and yes, it’s true. Maybe Western Digital has changed the density of NANDs and I think they keep the same controller (so a tri-core and four-channel in-house), but not changed completely the NANDs (from 96L to 64L, for example, or even from TLC to QLC, but Kioxia BiCS4 QLC are not very widespread).

 

@NewMaxxwhat’s your take about this?

[chan_QAQ]

22 minutes ago, Wooden Law - Black said:

这在一个中文视频中得到了解释，是的，这是真的。也许西部数据改变了 NAND 的密度，我认为他们保留了相同的控制器（所以内部有一个三核和四通道），但没有完全改变 NAND（例如从 96L 到 64L，甚至从TLC 到 QLC，但 Kioxia BiCS4 QLC 不是很普遍）。

 

@NewMaxx你怎么看这件事？

I have seen someone  speculation them used 112 layers of BICS5, because they wanted to make enough capacity with fewer dies

[Wooden Law - Black]

1 hour ago, chan_QAQ said:

I have seen someone  speculation them used 112 layers of BICS5, because they wanted to make enough capacity with fewer dies

Also in this case, BiCS5 aren’t very widespread, but there’s a probably since SanDisk collaborates with Kioxia (ex-Toshiba) for NANDs production (in fact all WD/SanDisk SSDs have Kioxia/Toshiba NAND), so all WD/SanDisk SSDs use only that NANDs.

 

BiCS5 are better than BiCS4 because BiCS5 is four-plane architecture vs dual-plane architecture (and it improving the interleaving), it has a higher MB/s per die (132 MB/s vs 57 MB/s), it has a smaller die size (and a higher bit density) and also the bus speed has improved, from 800 MT/s to 1066 MT/s (96L are usually 800 MT/s, these NANDs that has 112L instead 128L are 1066 MT/s, while 128L are usually 1200 MT/s).