Corsair EX400U Survivor 1TB portable SSD
Here you will find a detailed speed, performance and benchmark test review. Tested was the portable SSD EX400U Survivor with 1TB (CSSD-EX400US1TB) from the brand Corsair.
| Technical specifications (manufacturer information) | |
| Product image | 
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| Manufacturer | Corsair |
| Model number | CSSD-EX400US1TB |
| Capacity | 1024 GB (931 GiB) |
| pSLC cache | 50 GB approx. |
| Read speed | 4000 MB/s |
| Write speed | 3500 MB/s |
| Interface | USB 4.0 Gen 3x2 (40 Gbit/s) |
| Connector | USB Typ C |
| Dimensions (LxWxH) | 82 x 40 x 17 mm (=3.23 x 1.57 x 0.67 in) |
| Weight | 81 gram (=2.86 oz) |
Compare product Compared to the test winner*
We put the Corsair 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 2967 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 2026 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 |
1,602.84 MB/s |
1.43 s |
| Program typical program folder with many small files |
120.94 MB/s |
58.20 s |
| Game a game folder with small and large files |
655.00 MB/s |
10.55 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 specs: 4000 MB/s and 3500 MB/s) the portable SSD is measured.
| CDM | Read [MB/s] | Write [MB/s] |
|---|---|---|
| SEQ1M Q8T1 |
4,062.15 |
3,625.01 |
| SEQ1M Q1T1 |
2,158.06 |
3,096.32 |
| RND4K Q32T16 |
641.45 |
886.61 |
| RND4K Q1T1 |
39.10 |
120.41 |
IOPS (Input/Output operations per second)
| CDM | Read [IOPS] | Write [IOPS] |
|---|---|---|
| SEQ1M Q8T1 |
3,874.00 |
3,457.10 |
| SEQ1M Q1T1 |
2,058.10 |
2,952.90 |
| RND4K Q32T16 |
156,604.00 |
216,457.00 |
| RND4K Q1T1 |
9,546.40 |
29,396.70 |
Average latency
| CDM | Read [µs] | Write [µs] |
|---|---|---|
| SEQ1M Q8T1 |
2,063.41 |
2,306.54 |
| SEQ1M Q1T1 |
485.58 |
338.44 |
| RND4K Q32T16 |
3,247.31 |
2,320.43 |
| RND4K Q1T1 |
104.57 |
33.90 |
ATTO Disk Benchmark
Here, a 256 MB file is written to the Corsair 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 Corsair 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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