This is the cable I got to allow me to work through the stack of old notebook drives I have accumulated, and am consolidating/cleaning before I thoroughly wipe them and donate somewhere.
Amazon.com: Sabrent USB 3.0 to SSD / 2.5-Inch SATA I/II/IIIHard Drive Adapter (EC-SSHD): Computers & Accessories
So, no, a true clone will not clean up the drive, but it simply will allow you to defer the cleanup, if it's simply a drive space issue. Once your system drive is at 90%, things are going to slow down a lot because it's just hard to manage swap files, defragging, etc.. (And fragmentation is really a non-issue with SSDs, so I assume the OS has the smarts to turn that [de-frag] off, saving one background process.)
Rotating media used to be faster than SSDs, and it's certainly fast enough for audio, so long as it's not filled and fragmented. But, you're not using it for audio, so it's possible it's just too full to operate efficiently. And, I doubt there's a lot of R&D money going into HDD development these days and they're probably installing 5400RPM drives with minimal cache - could be wrong there.
Anyway, SSDs are the present. Molecular, bubble, plasma something is the future. Spinners are like buggy-whips Dave
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