Seagate Ultra Compact SSD 1TB portable SSD
Here you will find a detailed speed, performance and benchmark test review. Tested was the portable SSD Ultra Compact SSD with 1TB (STMX1000400) from the brand Seagate.
| Technical specifications (manufacturer information) | |
| Product image | 
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| Manufacturer | Seagate |
| Model number | STMX1000400 |
| Capacity | 1024 GB (931 GiB) |
| pSLC cache | 40 GB approx. |
| Read speed | 1000 MB/s |
| Write speed | 1000 MB/s |
| Connector | USB Typ C |
| Dimensions (LxWxH) | 70 x 20.4 x 12.5 mm (=2.76 x 0.80 x 0.49 in) |
| Weight | 17 gram (=17 oz) |
| Controller | n/a |
Compare product Compared to the test winner*
We put the Seagate portable SSD through a detailed test. You can find the test result / test report here:
AS SSD Benchmark
Standard performance test
The standard test was performed with a 5 GB file. A total score of 1103 points was achieved.
Copy performance test
A common everyday scenario is simulated here. Three test folders are created:
- ISO (folder with two large files)
- Program (folder with many small files)
- Game (folder with small and large files)
The three folders are copied using the Windows copy command (cache remains enabled). The real-world test from 08 April 2025 shows performance during simultaneous write and read operations. The lower the duration, the better.
| AS SSD Copy Benchmark | Transfer rate: | Duration: |
|---|---|---|
| ISO two large files |
649.72 MB/s |
3.54 s |
| Program typical program folder with many small files |
107.36 MB/s |
65.57 s |
| Game a game folder with small and large files |
362.45 MB/s |
19.06 s |
Compression performance test
Here, speed is measured depending on how compressible the data is.
CrystalDiskMark Benchmark
Similar to AS SSD, two sequential and two random performance tests are carried out here and the write and read speed (manufacturer: 1000 MB/s and 1000 MB/s) the portable SSD is determined.
| CDM | Read [MB/s] | Write [MB/s] |
|---|---|---|
| SEQ1M Q8T1 |
1,014.18 |
1,026.02 |
| SEQ1M Q1T1 |
787.04 |
980.33 |
| RND4K Q32T16 |
282.55 |
401.21 |
| RND4K Q1T1 |
31.54 |
101.06 |
IOPS (Input/Output operations per second)
| CDM | Read [IOPS] | Write [IOPS] |
|---|---|---|
| SEQ1M Q8T1 |
967.20 |
978.50 |
| SEQ1M Q1T1 |
750.60 |
934.90 |
| RND4K Q32T16 |
68,982.20 |
97,952.60 |
| RND4K Q1T1 |
7,700.40 |
24,671.60 |
Average latency
| CDM | Read [µs] | Write [µs] |
|---|---|---|
| SEQ1M Q8T1 |
8,264.02 |
8,155.12 |
| SEQ1M Q1T1 |
1,331.77 |
1,068.98 |
| RND4K Q32T16 |
7,411.05 |
5,222.59 |
| RND4K Q1T1 |
129.73 |
40.42 |
HD Tune Pro long-term test
A long-term test was performed to fully utilize the storage. You can see from when a possible cache is full and write performance drops. A test file of 100 GB was written to the medium. After approx. 40 GB, the cache was full and performance was throttled.
The test file could at least be read with an average read speed of 934 MB/s and written at 611 MB/s.
HD Tune Pro Benchmark
HD Tune writes a 5 GB file to the Seagate portable SSD. The transfer data of the read speed is displayed graphically. The minimum, maximum and average values are also determined. The measured access time and burst rate are also shown.
ATTO Disk Benchmark
Here, a 256 MB file is written to the Seagate portable SSD multiple times. The I/O block size varies (from 512 bytes to 64 megabytes). The larger the blocks, the faster writing and reading usually becomes.
SSD-Z Benchmark
Similar to HD Tune, a 500 MB file is written to the Seagate portable SSD here. The transfer data is displayed. The more consistent the line, the better. Unfortunately, the tool no longer works correctly from around 4,000 MB/s and no line is displayed (and sometimes incorrect min/max data is shown).
You can find information about the test system at the bottom of the homepage.
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