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Pm991a

NVMe Samsung 256GB

▲ 500 ▼

Release date ≈ Q4 2020.

Average Bench: 122% (188th of 1072)

Based on 1,767 user benchmarks.  Model: PM991a NVMe Samsung 256GB
Poor: 61%Average: 122% Great: 199%

Popular builds with this SSD

Outstanding average bench

The Pm991a NVMe Samsung 256GB averaged 21.5% higher than the peak scores attained by the group leaders. This is an excellent result which ranks the Pm991a NVMe Samsung 256GB near the top of the comparison list.

Strengths

Avg. 4K-64Thread Mixed IO Speed 388MB/s
Avg. 4K-64Thread Read Speed 563MB/s

Terrible consistency

The range of scores (95th - 5th percentile) for the Pm991a NVMe Samsung 256GB is 139%. This is a particularly wide range which indicates that the Pm991a NVMe Samsung 256GB performs inconsistently under varying real world conditions.

Weaknesses

Avg. Sustained Write Speed 280MB/s
Avg. 4K Random Write Speed 77.6MB/s
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Average Bench

(Based on 1,767 samples)
Rank 188122%
Min Avg Max
493 Read 998 1,481
93.6 Write 559 1,152
166 Mixed 572 1,163
82.5 SusWrite 280 558
134% 602 MB/s
Min Avg Max
14.2 4K Read 37.3 53.4
26.8 4K Write 77.6 141
14.8 4K Mixed 39.9 70.6
149% 51.6 MB/s
Min Avg Max
188 DQ Read 563 885
80 DQ Write 304 953
126 DQ Mixed 388 816
301% 418 MB/s
User Benchmarks BenchSequentialRandom 4kDeep queue 4k
The fastest SSD (mainstream) averages a speed of 100%
167GB free (System drive)
Firmware: 26302039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 1104 1135 495 149 164 158 MB/s
210% Outstanding
Read 1,542
Write 1,201
Mixed 1,179
SusWrite 534
249% 1,114 MB/s
4K Read 50.5
4K Write 131
4K Mixed 70.3
236% 83.9 MB/s
DQ Read 882
DQ Write 1,010
DQ Mixed 812
649% 901 MB/s
207GB free (System drive)
Firmware: 26300039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 725 712 732 715 259 138 MB/s
123% Outstanding
Read 859
Write 676
Mixed 683
SusWrite 547
155% 691 MB/s
4K Read 28.5
4K Write 55
4K Mixed 32.4
114% 38.6 MB/s
DQ Read 548
DQ Write 354
DQ Mixed 466
343% 456 MB/s
206GB free (System drive)
Firmware: 26302039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 562 563 573 564 483 127 MB/s
123% Outstanding
Read 740
Write 611
Mixed 624
SusWrite 479
138% 614 MB/s
4K Read 38.8
4K Write 69.4
4K Mixed 50.7
160% 53 MB/s
DQ Read 372
DQ Write 232
DQ Mixed 304
226% 303 MB/s
116GB free (System drive)
Firmware: 26304039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 145 121 136 129 125 138 MB/s
91.9% Outstanding
Read 792
Write 179
Mixed 277
SusWrite 132
75% 345 MB/s
4K Read 30.8
4K Write 68.6
4K Mixed 34.8
128% 44.7 MB/s
DQ Read 478
DQ Write 101
DQ Mixed 262
199% 280 MB/s
21GB free (System drive)
Firmware: 26300039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 98 73 67 64 66 66 MB/s
85.8% Excellent
Read 724
Write 148
Mixed 222
SusWrite 72.1
63% 291 MB/s
4K Read 31.9
4K Write 72.5
4K Mixed 32.6
128% 45.7 MB/s
DQ Read 480
DQ Write 116
DQ Mixed 157
152% 251 MB/s
26GB free (System drive)
Firmware: 26300039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 108 90 85 83 78 72 MB/s
81.2% Excellent
Read 677
Write 180
Mixed 216
SusWrite 86.1
63% 290 MB/s
4K Read 28.8
4K Write 64.6
4K Mixed 30.4
117% 41.3 MB/s
DQ Read 448
DQ Write 144
DQ Mixed 174
160% 255 MB/s
47GB free (System drive)
Firmware: 26304039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 154 126 102 93 90 76 MB/s
76.1% Very good
Read 682
Write 204
Mixed 262
SusWrite 107
68% 314 MB/s
4K Read 17.5
4K Write 74.8
4K Mixed 23.7
96% 38.7 MB/s
DQ Read 488
DQ Write 94.8
DQ Mixed 253
196% 279 MB/s
131GB free (System drive)
Firmware: 26302039 Max speed: PCIe 16,000 MB/s
SusWrite @10s intervals: 128 126 119 103 121 112 MB/s
62.7% Good
Read 677
Write 179
Mixed 230
SusWrite 118
66% 301 MB/s
4K Read 15.4
4K Write 43.5
4K Mixed 19.6
72% 26.2 MB/s
DQ Read 168
DQ Write 120
DQ Mixed 149
110% 146 MB/s
1,767 MORE »

 Market Share (See Leaders)

The number of benchmark samples for this model as a percentage of all 75,715,463 SSDs tested

Custom PC Builder (Start a new build) Build your perfect PC: compare component prices, popularity, speed and value for money

CHOOSE A COMPONENT:

CPU GPU SSD HDD RAM MBD
Typical NVMe Samsung 256GB Builds (Compare 703 builds) See popular component choices, score breakdowns and rankings
Gaming
Gaming 13%
Tree trunk
Desktop
Desktop 74%
Battleship
Workstation
Workstation 11%
Tree trunk

System: Dell Inspiron 5400 AIO

CPU
Core i5-1135G7IntelBench 69%, 36,962 samples310x
Core i7-1165G7IntelBench 66%, 51,565 samples242x
Core i3-1115G4IntelBench 51%, 18,815 samples129x
GPU
Iris XeIntelBench 14%, 144,774 samples511x
UHD GraphicsIntelBench 9%, 39,662 samples151x
GeForce MX330NvidiaBench 14%, 4,518 samples41x
SSD
NVMe Samsung 256GBPm991aBench 122%, 1,767 samples67x
RAM
HMAA1GS6CJR6N-XN 1x8GBUnknownBench 32%, 13,137 samples94x
4ATF1G64HZ-3G2E2 1x8GBUnknownBench 38%, 2,458 samples36x
HMAA1GS6CJR6N-XN 2x8GBUnknownBench 65%, 26,875 samples34x
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Popular NVMe Samsung 256GB systems:

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Welcome to our 2.5" and M.2 SSD comparison. We calculate effective speed for both SATA and NVMe drives based on real world performance then adjust by current prices per GB to yield a value for money rating. Our calculated values are checked against thousands of individual user ratings. The customizable table below combines these factors to bring you the definitive list of top SSDs. [SSDrivePro]

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  • Best user rated - User sentiment trumps benchmarks for this comparison.
  • Best value for money - Value for money is based on real world performance.
  • Fastest real world speed - Real World Speed measures performance for typical consumers.

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 Frequently Asked Questions

Storage Devices FAQ
What is sustained sequential write speed?
What’s the difference between SLC, MLC and TLC?
What is 3D XPoint and how fast is it?
What’s the difference between SATA, PCIe and NVMe?
What’s the difference between NAND and V-NAND?
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What is sequential read speed?
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 Best User Rated
The Best.
CPUGPUSSD
Intel Core i5-13600K $273Nvidia RTX 4060 $300Crucial MX500 250GB $40
Intel Core i5-12400F $133Nvidia RTX 4060-Ti $385Samsung 850 Evo 120GB $80
Intel Core i5-12600K $177Nvidia RTX 4070 $539Samsung 860 Evo 250GB $52
HDDRAMUSB
Seagate Barracuda 1TB (2016) $39Corsair Vengeance LPX DDR4 3200 C16 2x8GB $45SanDisk Extreme 64GB $72
WD Blue 1TB (2012) $37Corsair Vengeance LPX DDR4 3000 C15 2x8GB $43SanDisk Extreme 32GB $28
Seagate Barracuda 2TB (2016) $51G.SKILL Trident Z DDR4 3200 C14 4x16GB $351SanDisk Ultra Fit 32GB $16
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