> If there aren't too many different manufacturers might be worth
> seeing what the manufacturers utilities offer, as a built-in wipe may be
> faster.
>
> Theoretically if you have trim enabled most of the blocks containing
> the data will be erased anyway. (You could write one sector per erase
> block size to check.)
I must admit I've never considered using manufacturer utilities at all, partly because I'm suspicious of them, and just delete all preinstalled files off the drives. Every single drive was a different make and model - they were test units I'd bought to decide which to buy in bulk.
I'd never heard of Trim before, but it appears it's enabled on the Windows 10 machine I used the drives on (fsutil behavior query DisableDeleteNotify gave a 0 result), so I guess the drives may have already been cleaned after I deleted the files.
When does the drive do the Trim cleaning? If I had deleted the files then immediately "ejected" the drive ,would the cleaning have been done? If not, does it remember which blocks need erasing, and do it next time it's got power?