Toshiba BG4 KBG40ZNS128G

The Toshiba KBG40ZNS128G is a very compact (single side M.2 22x30 mm) SSD for tablets, laptops, IoT devices. We found the 128 GB drive's performance to be subpar in our independent testing conducted in 2019.


The NVMe class drive (PCI-E 3.0 x4) fell short of its rated capabilities in our testing. While Toshiba/Kioxia promises read and write rates of up to 2000 MB/s and 800 MB/s respectively, the real world results do not get anywhere near those targets, lagging behind many SATA III class drives in a few scenarios.

Power Consumption

The consumption should be relatively low at around 3 W (according to the manufacturer). Nonetheless, the drive will probably see a lot of thermal throttling throughout its useful life span, just as most M.2 SSDs do.

Notebookcheck says:

... While sequential read rates on the SSD are decent at about 1200 MB/s, sequential write rates are slower than even most SATA III SSDs at just under 200 MB/s. This is a budget drive after all with similar results to the Toshiba BG3 found on the Dell G7 17 7790 - Dell G3 15 3590 Laptop Review, 2019

LinkToshiba BG4 KBG40ZNS128G


AS SSD - Copy Game
166 MB/s (3%)
AS SSD - Copy Program
108 MB/s (4%)
216 MB/s (6%)
AS SSD - Score Total
987 Points (13%)
AS SSD - Score Write
157 Points (4%)
AS SSD - Score Read
575 Points (22%)
AS SSD - Access Time Write *
0.9 ms (0%)
AS SSD - Access Time Read *
0.2 ms (0%)
AS SSD - 4K-64 Write
68.8 MB/s (2%)
AS SSD - 4K-64 Read
424 MB/s (19%)
AS SSD - 4K Write
69.4 MB/s (1%)
AS SSD - 4K Read
34 MB/s (13%)
AS SSD - Sequential Write
186 MB/s (4%)
AS SSD - Sequential Read
1174 MB/s (24%)
- Range of benchmark values for this graphics card
- Average benchmark values for this graphics card
* Smaller numbers mean a higher performance

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Notebook reviews with Toshiba BG4 KBG40ZNS128G

Dell G3 3590: Intel Core i5-9300H NVIDIA GeForce GTX 1650 Mobile, 15.6", 2.5 kg
  Review » Dell G3 15 3590 Laptop Review: Inexpensive with Easy Upgrades

  External Review » Dell G3 3590

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> Notebook / Laptop Reviews and News > Benchmarks / Tech > Laptop harddisks (HDD, SSD) benchmarks > Toshiba BG4 KBG40ZNS128G Benchmarked
Klaus Hinum (Update: 2020-03- 1)