Western Digital Blue SN5000 4TB Gen 4 SSD Review – TLC or QLC Memory – You Pick

Western Digital has recently released it’s newest Blue SN5000 NVMe SSD in a PCIe 4.0 design and, although there isn’t much to scream and shout about, this SSD is a bit different from the rest.  It relies on two separate types of memory, depending on the chosen size.  If you are buying the SN5000 from 500GB to the 2TB capacity, the memory in use is KIOXIA 112-layer 3D TLC BiCS 5.  If you want the higher capacity 4TB SN5000,  you get the newest 162-layer BiCS 6 3D QLC memory.  The reason of course is that BiCS6 memory is 40% smaller than BiCS 5 which allows the M.2 form factor to accommodate a full 4TB as a single sided SSD.

We have the 4TB capacity on our bench today and, quite frankly, for a QLC variant, it has some punch.  I certainly never expected such performance from a QLC SSD.  It is a single-sided SSD with two small 2TB BiCS 6 chips, an even smaller in-house PCIe 4 NVMe controller which also means something else that is rather refreshing.  This SSD does not require any cooling solution.  You can throw it in to an ultrabook for 5.5GB/s speeds and 4TB capacity without a concern.  Did we mention that this SSD is DRAM-less?


The WD Blue SN5000 is a 4-channel PCIe 4.0 SSD that is set into a 2280 (22mm wide by 80mm long) form factor and uses the latest NVMe 2.0 protocol.  It is now available in capacities of 500GB, 1TB, 2TB and 4TB and as mentioned, all capacities but the 4TB use KIOXIA BiCS 5 3D TLC NAND flash memory whereas the 4TB version relies on the latest QLC BiCS 6.  Performance is variable for every capacity as shown in this chart below:


Testing should be rather interesting as our 4TB sample speaks to 5.5GB/s read and 5GB/s for a QLC and DRAMless SSD, but there is something worthy of note with respect to endurance.  Typically with SSDs, we see the endurance double when jumping to the next capacity, however, for this SSD the 2TB is 900TBW whereas the 4TB is only 1200TBW (and not 1800TBW).  This is the result of WD’s choice to use QLC memory rather than TLC memory, however, this shouldn’t dissuade anyone as that is still alot of use in itself.  It is extremely rare that anyone has ever seen SSDs reach end life…  No worry though as this SSD comes with a limited 5-year warranty.


Perhaps the success of the 4TB SN5000 lies in its use of Western Digital’s proprietary nCache 4.0 software which would allow for creative workflows and an AI-enabled experience.  The SN5000 also conforms to the TCG Pyrite 2.01 storage specification.  Looking at the SSD void of branding sticker we see only two NAND chips, each having a 2GB RAW value, as well as a very small in-house Gen 4 NVMe SSD controller.


Checking Amazon, we see WD Blue SN5000 pricing at $93 (500GB), $105.35 (1TB), $93.50 (2TB) and $360.94 for the 4TB sample.  That price for the 2TB version might be a mistake but was definitely that listed at the time of this report…

Now let’s check out the performance of this QLC DRAMless WD Blue SN5000 SSD…

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