The fastest speed indicated on the Transcend website may differ from the actual transfer speed you experience. This is because the fastest speed listed on the website is based on tests conducted using benchmarking software with the highest-spec devices. However, during actual usage, transfer speed can be influenced by various factors, including system performance (hardware, software, usage, and storage capacity), file types, sizes, and quantities. Therefore, the actual transfer speed may vary.
If the write speed of your portable SSD (ESD) drops to about 60–100MB/s, please refer to the following instructions. (You can measure the speed via speed test software.)
1. Reasons for write speed drop:
- The SLC cache got exhausted: Portable SSDs (ESD) have an SLC cache mechanism. If a specific capacity is used or a large amount of data is written in a single power-on, cache blocks might run out. Afterward, these drives will write slower as TLC blocks. (about 60–100 MB/s). If you have higher speed requirements, consider purchasing a larger-capacity portable SSD, as this will increase the size of the SLC cache accordingly. Figure 1 displays the transfer speed shown by Windows during data transfer. It is calculated in real time based on the file transferred and may differ from the speed indicated by benchmarking software.
Figure 1. The slowdown in speed due to the depletion of the SLC cache.
- Use SSDs as system drives: Portable SSDs (ESD) are not system drives but consumer products mainly designed for transferring files.If you use them as system drives, many small files will be read and written, and the portable SSDs (ESD) cache blocks will also be exhausted faster, affecting the write performance.In addition, if users use them as system drives to keep writing a large number of small files, it will not help speed up SSDs because consuming cache blocks will be much faster than clearing out cache blocks.
2. Solutions to restore speed
- We recommend deleting unnecessary data to free up more space. The likelihood of slowdowns will decrease after leaving the external solid-state drive (ESD) powered on but idle for 10-30 minutes.
- We suggest using the operating system's built-in formatting tool to format. Please note: Formatting will delete all data stored on the device, so be sure to back up your data before performing this procedure.