Component change in SSDs: WD Blue SN550 and Samsung SSD 970 Evo Plus


Western Digital has recently equipped the entry-level SSD WD Blue SN550 with new memory, while Samsung has replaced the memory and controller in its own SSD 970 Evo Plus model of the upper middle class. Both are M.2 cards that use four PCI Express 3.0 lanes.

While Samsung’s new edition does not fare worse per se and is clearly identifiable thanks to the new product number and packaging, Western Digital offers a worse SSD that cannot be identified before buying.

So shows a Test of the Chinese language website Expreviewthat the WD Blue SN550 with 1 TB capacity only writes at just under 400 MB / s as soon as the 12 GB small SLC cache is full. The latter only describes 1 instead of 3 bits per memory cell (single vs. triple level cells) in order to increase performance. The earlier version, on the other hand, achieved around twice the value. Only the first 12 GB can be copied to the SSD with the full performance of just under 2.2 GB / s.

In a Opinion to Computer base Western Digital confirms the observations and promises improvement. In the future, SSDs will receive new model numbers when changing components. Last year, Western Digital was repeatedly noticed by the deterioration of its own HDDs – only after a lot of criticism and class actions did the manufacturer improve transparency.

In the case of Samsung’s SSD 970 Evo Plus, a Chinese-language Youtube channel on the changes attentive to the 1 TB model (the English subtitle is useful). The product number will therefore change from MZVLB1T0HBLR to MZVL21T0HBLU; the packaging differs significantly. Samsung assembled the old version in China (“Made in China”), the new one in South Korea (“Made in Korea”).

The different versions of Samsung’s SSD 970 Evo Plus can be clearly distinguished from the outside (old on the left, new on the right)

(Image: Youtube-Kanal Trendy Player)

Samsung is replacing the previous Phoenix controller from its own development with the newer Elpis, which the company had introduced with the SSD 980 Pro – but downgraded from PCIe 4.0 to PCIe 3.0 for the 970 model. The change could be a result of the loss of production in the Texas semiconductor plant, where Samsung manufactures SSD controllers, among other things.

The NAND flash modules also differ: they used to be labeled with K9DUGY8J5B-DCK0, now with K9DUGY8J5B-CCK0. Details are not known – a change from the 5th generation V-NAND to the newer 6th generation would be conceivable.

The new edition is faster as long as you don’t often write very large files to the SSD: Samsung has increased the SLC cache from around 40 to 115 GByte with enough free capacity. Within this intermediate buffer, the new SSD 970 Evo Plus achieves almost 2.6 GB / s in the HD Tune Pro benchmark, the old 1.7 to 1.8 GB / s. If this cache is full, however, the performance now drops more – to around 800 MB / s instead of 1.5 GB / s. The test tool CrystalDiskMark certifies that the new edition has a significantly higher write performance even with small write processes.


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