I'm writing this from memory, so some details may be wrong but: most high end ssds have dram caches on board, with a capacitor that maintains enough charge to flush the cache to flash in case of power failure. This operates below the system page cache that is standard for all disks and oses.

Apple doesn't do this, and use their tight integration to perform a similar function using system memory. So there is some technical justification, I think. They are 100% price gougers though.

Using host memory for SSD caches is part of the NVMe spec, it's not some Apple-magic-integration thing: https://www.servethehome.com/what-are-host-memory-buffer-or-...

It's also still typically just worse than an actual dram cache.

> writing this from memory

Gave me a chuckle ;)

One company's "Price Gouging" is another's "Market Segmentation"

Probably, but since we're talking about an Apple product, comparing it to macOS make sense, since they all share the same bottom layer.

Not, probably, that just how any "modern" OS works. It also uses RAM as a cache to avoid reads from storage, just like any other modern OS.

Apple uses it for segmentation and nothing else.

Modern being - since the 80s.

Even on the Atari ST you would use a "RAM disk" when working with "large" data before manually flushing it to a floppy. Some people would use the trashcan icon to emphasise the need to manually flush... Not quite a cache, but the concept was there.