3 ms·

Flash memory is usually rated to what, order of 100,000 write cycles? But it has much better endurance on reads. If they aren't used as something like a pagefil

Flash memory is usually rated to what, order of 100,000 write cycles? But it has much better endurance on reads. If they aren't used as something like a pagefile, they can usually last awhile. But I guess it depends on the use case, and I'm assuming this will be similar to what exists now.

imtringued 9y ago
Maybe if you have an expensive high end enterprise SLC SSD. Consumers use the cheapest SSDs available and that's usually TLC with 5000 or less write cycles and soon we will be on QLC which will only have up to 1000 cycles. The more bits a cell stores and the smaller the manufacturing process the lower the amount of write cycles. 2D NAND hit a scaling brickwall and the only way to scale NAND is now to stack layers on top of each other. Obviously SD cards are even worse than SSDs when it comes to reliability.
- userbinator 9y ago
  5K~10K was MLC 8 years ago[1], and there's evidence that some cheaper/smaller-geometry flash didn't even make it that far[2] Now, it's more like ~1K for (good) TLC and closer to 100 for QLC. There are no official numbers I can find on TLC/QLC endurance or retention (besides a lot of handwavy and weasel-worded marketing saying it's "good enough"), but the degradation is exponential with the number of bits, not multiplicative, so one can make an educated guess. [1] http://www.farnell.com/datasheets/1382714.pdf http://www.farnell.com/datasheets/1382714.pdf note date, and see page 3. [2] http://pdf.dzsc.com/88888/2008422102742719.pdf http://pdf.dzsc.com/88888/2008422102742719.pdf also note date, and look at 3rd item in the revision history
  - wtallis 9y ago
    Toshiba says their upcoming 3D QLC NAND will be good for about 1k P/E cycles. But like most recent P/E ratings, that's almost certainly given under the assumption that you're using LDPC error correction or something equally robust, so you can't compare directly to the ratings for older SLC NAND.
- leggomylibro 9y ago
  Huh, wow. I was going off of the datasheets for flash chips I've been using, but I guess things are different for really high-density ones.

imtringued 9y ago

Maybe if you have an expensive high end enterprise SLC SSD. Consumers use the cheapest SSDs available and that's usually TLC with 5000 or less write cycles and soon we will be on QLC which will only have up to 1000 cycles. The more bits a cell stores and the smaller the manufacturing process the lower the amount of write cycles. 2D NAND hit a scaling brickwall and the only way to scale NAND is now to stack layers on top of each other. Obviously SD cards are even worse than SSDs when it comes to reliability.

userbinator 9y ago
5K~10K was MLC 8 years ago[1], and there's evidence that some cheaper/smaller-geometry flash didn't even make it that far[2] Now, it's more like ~1K for (good) TLC and closer to 100 for QLC. There are no official numbers I can find on TLC/QLC endurance or retention (besides a lot of handwavy and weasel-worded marketing saying it's "good enough"), but the degradation is exponential with the number of bits, not multiplicative, so one can make an educated guess. [1] http://www.farnell.com/datasheets/1382714.pdf http://www.farnell.com/datasheets/1382714.pdf note date, and see page 3. [2] http://pdf.dzsc.com/88888/2008422102742719.pdf http://pdf.dzsc.com/88888/2008422102742719.pdf also note date, and look at 3rd item in the revision history
- wtallis 9y ago
  Toshiba says their upcoming 3D QLC NAND will be good for about 1k P/E cycles. But like most recent P/E ratings, that's almost certainly given under the assumption that you're using LDPC error correction or something equally robust, so you can't compare directly to the ratings for older SLC NAND.
leggomylibro 9y ago
Huh, wow. I was going off of the datasheets for flash chips I've been using, but I guess things are different for really high-density ones.