WD’s swap-out was first discovered and posted on the Chinese tech site, EXPReview, who noticed that the newer version of the SN550 Blue SSD it has, was performing slightly worse than other NVMe SSDs in the same range, particularly when it came to copying large files. Technically speaking, it found that both old and new versions of the SN550 were able to achieve their listed write speeds of 2.1GB/s, so long as the transfer doesn’t exceed the 12GB SLC cache size. When it did exceed the cache size and the SSD started writing without the cache, the transfer speeds dramatically dropped from 610MB/s to less than half its speed at 390MB/s.
In comparison, EXPReview says that those reduced speeds are more in line with WD’s SN350 Green SSD, and now the SN550 Blue. And while the issue only rears its ugly head whenever the files are large, it is fair to say that this isn’t a plausible excuse for WD to begin swapping out the NAND controller, even more so without telling consumers or reviewers about it. This isn’t the first time WD has come under fire for such covert actions either. Last year, the company was slapped with lawsuits in the US and Canada, when it came to light that it had been selling SMR-based NAS HDDs, without fully disclosing it to the public. These HDDs theoretically run 13 times slower than the typical CMR-based HDD, and are thus considered unsuitable for both NAS applications and other RAID deployments. (Source: EXPReview via Techspot)
