What should I do if the USB 3.0 flash drive is too slow when copying files?

The newly purchased USB 3.0 flash drive fails to achieve the expected file copying speed. You can improve the transmission performance by optimizing the system settings.

The specific steps are as follows:

Step 1: Confirm hardware and interface compatibility
First, eliminate physical layer issues. The theoretical bandwidth of the USB3.0 interface is 5Gbps (approximately 625MB/s), but the actual speed is limited by the U盘's main control chip, the type of flash memory (such as TLC/MLC), and the interface standard. If a USB2.0 interface is used or the computer motherboard only supports USB3.0 Gen1 (5Gbps) instead of Gen2 (10Gbps), the transmission rate will significantly decrease. It is recommended to insert the U disk into the rear USB3.0 interface (usually a blue socket) to avoid connecting through the front panel or an expansion dock.

Step 2： Enable write caching function
The Windows system disables write caching for removable storage devices by default to prevent data loss, but this setting limits the transmission speed. The operation path is as follows：
Open "This PC", right-click on the U disk icon, select "Properties";
Switch to the "Hardware" tab, select the U disk device, and click "Properties";
In the "Policy" tab, check "Better performance" and enable "Enable write caching on the device" (note： some U disks due to control limitations may not support this function; if the option is grayed out, it cannot be adjusted);
Click "OK" to save the settings.
This operation allows the system to temporarily store data before writing it to the U disk, which can significantly improve the continuous write speed, but ensure that the data is transferred completely before safely removing the device; otherwise, the un-written data may be lost.
Step 3： Check file system and fragmentation status
If the U disk uses the FAT32 format, single files over 4GB will be transmitted in blocks, resulting in speed fluctuations. It is recommended to format the U disk into the NTFS or exFAT file system (backup data before operating). Additionally, frequent and long-term writing may lead to flash memory fragmentation, and you can perform a fragmentation cleanup using the built-in "Optimize Drives" tool in Windows (only effective for NTFS format).

Step 4： Exclude interference from background programs
If antivirus software, cloud synchronization tools, or resource management index services are running simultaneously during the transfer, they will occupy the USB bandwidth. It is recommended to close unnecessary programs before retrying the test.

Step 5： Verify actual performance
Use professional benchmarking tools (such as CrystalDiskMark) to test and compare continuous read/write and 4K random read/write speeds. If the test results are still significantly lower than the nominal values, it may involve U disk under-marked parameters or quality issues. Contact the seller for verification.

Notes:

The cache writing function may increase the risk of data loss. For important files, it is recommended to "safely eject" them manually after the transmission is completed.
If the main control chip of the USB flash drive has poor performance (such as using a low-speed main control), even if the cache is enabled, it is difficult to reach the theoretical peak.
Excessive temperature will cause the flash memory to reduce its frequency. When transferring large files, a well-ventilated environment is required.