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2x 320GB vs Toshiba BG4 KBG40ZNS128G

2x 320GB

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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.

Performance

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

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2x 320GBToshiba BG4 KBG40ZNS128G
Capacity640 GB
RPM7200 rpm
InterfaceSATANVMe
TypeSSD
SizeM.2
Announced07.10.2019
LinkToshiba BG4 KBG40ZNS128G

Benchmarks

Performance Rating - DiskSpd - KBG40ZNS128G
11.7 pt (13%)
Seagate ST1000LM014 Solid State Hybrid Drive
0.709 -94%
...
Western Digital WD Blue 3D WDBNCE5000PNC
9.75 -17%
Samsung SSD 860 Evo 512GB
9.93 -15%
Crucial P2 1TB CT1000P2SSD8
10.2 -13%
SK hynix HFB1M8MQ331C0MR
10.4 -11%
Samsung SSD 860 Evo 256GB M.2
10.7 -9%
Apple SSD SM0512F
11.2 -4%
Kingston OM8SEP4256Q-A0
11.3 -3%
SK hynix BC501 HFM256GDGTNG
11.5 -2%
Apple SSD AP0512
11.5 -2%
Toshiba BG4 KBG40ZNS128G
11.7
Toshiba BG4 KBG40ZNT256G
11.9 2%
EDGE NextGen SSD 1TB
12.1 3%
Intel SSD 600p SSDPEKKW512G7
12.3 5%
SSSTC CL1-8D512-HP
12.5 7%
256 GB NVMe
12.9 10%
Silicon Power SP128GIMEA3K5EV0
13 11%
Toshiba KBG30ZMV256G
13 11%
Kingston RBUSNS8154P3512GJ
13.1 12%
Toshiba KBG30ZPZ128G
13.2 13%
...
Kingston Fury Renegade G5
87.4 647%
0%
100%
Restrict / Search: Model: Max. age: years
AS SSD - Copy Game
min: 165.9     avg: 171     median: 171 (3%)     max: 176 MB/s
AS SSD - Copy Program
min: 108.2     avg: 135.6     median: 135.6 (5%)     max: 163 MB/s
AS SSD - Copy ISO
min: 215.7     avg: 216.3     median: 216.3 (2%)     max: 216.8 MB/s
AS SSD - Score Total
min: 987     avg: 1136     median: 1135.5 (7%)     max: 1284 Points
AS SSD - Score Write
min: 157     avg: 273     median: 273 (4%)     max: 389 Points
AS SSD - Score Read
min: 575     avg: 595     median: 595 (10%)     max: 615 Points
AS SSD - Access Time Write *
min: 0.181     avg: 0.6     median: 0.6 (1%)     max: 0.94 ms
AS SSD - Access Time Read *
min: 0.124     avg: 0.1     median: 0.1 (0%)     max: 0.168 ms
AS SSD - 4K-64 Write
min: 68.8     avg: 135.9     median: 135.9 (2%)     max: 203 MB/s
AS SSD - 4K-64 Read
min: 424     avg: 442.6     median: 442.6 (9%)     max: 461.2 MB/s
AS SSD - 4K Write
min: 69.4     avg: 117.6     median: 117.6 (23%)     max: 165.7 MB/s
AS SSD - 4K Read
min: 34.01     avg: 36.8     median: 36.8 (12%)     max: 39.5 MB/s
AS SSD - Sequential Write
min: 186     avg: 192.9     median: 192.9 (2%)     max: 199.8 MB/s
AS SSD - Sequential Read
min: 1142     avg: 1158     median: 1158 (9%)     max: 1174 MB/s
CrystalDiskMark 5.2 / 6 - CDM 5/6 Write 4K
138.5 MB/s (13%)
CrystalDiskMark 5.2 / 6 - CDM 5/6 Read 4K
42 MB/s (1%)
CrystalDiskMark 5.2 / 6 - CDM 5 Write Seq
213.5 MB/s (1%)
CrystalDiskMark 5.2 / 6 - CDM 5 Read Seq
1289 MB/s (15%)
CrystalDiskMark 5.2 / 6 - CDM 5/6 Write 4K Q32T1
157.8 MB/s (5%)
CrystalDiskMark 5.2 / 6 - CDM 5/6 Read 4K Q32T1
448.9 MB/s (7%)
CrystalDiskMark 5.2 / 6 - CDM 5/6 Write Seq Q32T1
210.5 MB/s (1%)
CrystalDiskMark 5.2 / 6 - CDM 5/6 Read Seq Q32T1
1853 MB/s (10%)
HD Tune Transfer Rate Minimum - HD Tune Transfer Rate Minimum
100%
1  +
40.8 MB/s (2%)
HD Tune Transfer Rate Average - HD Tune Transfer Rate Average
100%
1  +
70.3 MB/s (3%)
HD Tune Transfer Rate Maximum - HD Tune Transfer Rate Maximum
100%
1  +
95.7 MB/s (4%)
DiskSpd - DiskSpd 4k_q1t1_write
121 MB/s (28%)
DiskSpd - DiskSpd 4k_q1t1_read
34.6 MB/s (10%)
DiskSpd - DiskSpd 4k_q32t16_write
163 MB/s (3%)
DiskSpd - DiskSpd 4k_q32t16_read
497 MB/s (6%)
DiskSpd - DiskSpd seq_write
240 MB/s (2%)
DiskSpd - DiskSpd seq_read
1336 MB/s (17%)
DiskSpd - DiskSpd seq_q8t1_write
241 MB/s (2%)
DiskSpd - DiskSpd seq_q8t1_read
1974 MB/s (12%)
DiskSpd - DiskSpd Loop seq_q8t1_read
1274 MB/s (8%)

Average Benchmarks 2x 320GB → 0% n=0

Average Benchmarks Toshiba BG4 KBG40ZNS128G → 0% n=0

- Range of benchmark values for this graphics card
red legend - Average benchmark values for this graphics card
* Smaller numbers mean a higher performance
1 This benchmark is not used for the average calculation

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#4 did not recreate cache, as it is less than 5 days old! Created at Sat, 26 Jul 2025 19:19:57 +0200 +0s ... 0s

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#12 min, max, avg, median took s +0.091s ... 0.102s

#13 return log +0.001s ... 0.103s

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> Expert Reviews and News on Laptops, Smartphones and Tech Innovations > Benchmarks / Tech > HDD/SSD Comparison - Head 2 Head
Redaktion, 2017-09- 8 (Update: 2023-07- 1)