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It seems that most of the high-end external SSD enclosures and external SSDs support UASP and TRIM/UNMAP.

Wikipedia does mention thumb drives but provides no further details:

USB Attached SCSI (UAS) or USB Attached SCSI Protocol (UASP) is a computer protocol used to move data to and from USB storage devices such as hard drives (HDDs), solid-state drives (SSDs), and thumb drives. UAS depends on the USB protocol, and uses the standard SCSI command set. Use of UAS generally provides faster transfers compared to the older USB Mass Storage Bulk-Only Transport (BOT) drivers.

However, I found nothing about usb flash drives that would support UASP and TRIM/UNMAP, despite there being a few high-performing flash drives that are marketed as having the "performance, capacity, and reliability of an SSD".

Are there any UASP USB flash drives with TRIM/UNMAP support?

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To get TRIM working over USB, you need to use the USB Attached SCSI protocol, and the OS (Windows 8+), USB controller, and adapter need to specifically support the SCSI UNMAP command.

I believe that there exists such adapters, enclosures and docks, or at least I found that StarTech has such enclosures.

The StarTech article All You Need to Know About UASP has this in the comments section:

Q: Do your UASP enclosures support translating the SCSI UNMAP command to TRIM? Otherwise SSDs in the enclosures won’t receive TRIM commands.

A: Yes, all of our single bay enclosures support TRIM commands.


For real flash drives, the vast majority of them do not have neither the hardware nor the firmware for Trim; they do Wear Leveling instead.

You need to go to the very highest quality level for Trim, for example the SanDisk Extreme SD UHS-I Card.

For example in the post sandisk extreme - memory stick has trim, is it an ssd?, it was analyzed as:

Crystal disk info says it has trim and it shows smart data, it`s only 16gb with a read speed of 245MB/s and write of 50MB/s.

  • Thank you, but my question is specifically about flash drives. – Jake F Nov 3 '18 at 18:57
  • I added a section about real flash drives with an example of one that does Trim. – harrymc Nov 3 '18 at 23:00

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