I should have been more clear: It's my http cache for my crawling jobs. Lots of files in many shapes.
My new setup: gen5 ssd in desktop:
> time find . -type f | wc -l
5645741
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Executed in 4.77 secs
My old setup, gen3 ssd in laptop: > time find . -type f | wc -l
2944648
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Executed in 27.53 secs
Both are running pretty much non-stop, very slowly.