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"As for disk speed, dd if=/dev/zero of=/tmp/output bs=128k count=50k; rm -f /tmp/output reports 1.6 GB/s which is 3.6x slower than my Mac Studio, and 3x slower than my Intel (which has the same M.2 stick). I'm told that Intel and Apple are just better at this, but I wish I understood why. "

Can anyone here answer why this is?

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Apple made fsync a noop.

You have to make a different call to get sync on macos.

So tons is stuff is faster because it's not actually writing to disk.

Plus he isn’t using oflag=direct, so since output file is small it isn’t even making it to disk. I think it would only be sent to page cache. I’m afraid he is testing CPU and memory (bus) speeds here.

oflag=direct will write direct and bypass page cache.

Exactly. Something is very fishy if this system only writes 1.6 GB/s to the page cache. Probably that dd command line quoted in the article is incomplete.

*she

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