Here you will find a detailed speed, performance and benchmark test review. Tested was the USB flash drive JetFlash 920 with 512GB (TS512GJF920) from the brand Transcend.
| Technical specifications (manufacturer information) | |
| Product image |
|
| Manufacturer | Transcend |
| Model number | TS512GJF920 |
| Capacity | 512 GB (466 GiB) |
| pSLC cache | 25 GB approx. |
| Read speed | 420 MB/s |
| Write speed | 400 MB/s |
| Interface | USB 3.2 Gen 1x1 (5 Gbit/s) |
| Connector | USB Typ A |
| Controller | n/a |
We put the 512 GB Transcend USB flash drive through a detailed test. You can find the test result / test report here:
The standard test was performed with a 1 GB file. A total score of 186 points was achieved.
A common everyday scenario is simulated here. Three test folders are created:
The three folders are copied using the Windows copy command (cache remains enabled). The real-world test from 10 October 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 |
288.71 MB/s |
3.72 s |
| Program typical program folder with many small files |
112.73 MB/s |
12.48 s |
| Game a game folder with small and large files |
208.13 MB/s |
6.64 s |
Here, speed is measured depending on how compressible the data is.
Similar to AS SSD, two sequential and two random performance tests are carried out here and the write and read speed (manufacturer: 420 MB/s and 400 MB/s) the Transcend USB flash drive is determined.

| CDM | Read [MB/s] | Write [MB/s] |
|---|---|---|
| SEQ1M Q8T1 |
363.58 |
369.65 |
| SEQ1M Q1T1 |
355.39 |
367.92 |
| RND4K Q32T16 |
37.70 |
28.75 |
| RND4K Q1T1 |
27.07 |
22.97 |
| CDM | Read [IOPS] | Write [IOPS] |
|---|---|---|
| SEQ1M Q8T1 |
346.70 |
352.50 |
| SEQ1M Q1T1 |
338.90 |
350.90 |
| RND4K Q32T16 |
9,204.30 |
7,017.80 |
| RND4K Q1T1 |
6,608.60 |
5,607.40 |
| CDM | Read [µs] | Write [µs] |
|---|---|---|
| SEQ1M Q8T1 |
22,990.80 |
22,598.00 |
| SEQ1M Q1T1 |
2,949.80 |
2,847.74 |
| RND4K Q32T16 |
55,257.30 |
72,242.70 |
| RND4K Q1T1 |
151.19 |
178.14 |
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 50 GB was written to the medium. After approx. 25 GB, the cache was full and performance was throttled.
The test file could at least be read with an average read speed of 314 MB/s and written at 224 MB/s.
Here, a 256 MB file is written to the 512 GB Transcend USB flash drive 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.

Similar to HD Tune, a 500 MB file is written to the 512 GB Transcend USB flash drive 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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