Discussion in 'Article Discussion' started by bit-tech, 21 Jun 2018.
Whole NGSFF is physically wider (and slightly thicker) than m.2 22110, electrically it is backward compatible and the card-edge connector is physically identical. If you can physically fit this SSD on your board (either due to fortuitous component placement or use of a flex riser) you could slot this into a desktop motherboard and have a tiny 8TB SSD for your ITX rig.
Which would presumably be powered by burning dollar bills, as if you can afford one of these SSDs you clearly are flush with cash.
The bigger double-take for me was not 8TB SSD but the 12 GIGABYTES of cache. To prove I wasn't going crazy, a 6TB 3.5in magnetic HDD seems to sport 256MB, while a 500GB Samsung Evo 860 has a whopping 512MB... obviously both of those options are circa £100, while this new drive (price TBC) will be expensivo, so easier to hide the extra cost of 12GB of LPDDR4.
AND YET, I just bought a OnePlus 6 with 8GB of rambo, and NVIDIA's just launched the Titan V with 32GB of VRAM, so why can't an SSD have 12GB...? #progress #640KB
It's not pure data cache, though: SSDs store the local and physical data maps in DRAM for performance and longevity reasons. The bigger your SSD, the more DRAM you need to hold said maps - and 8TB is pretty dang big. Intel's DC P4510 8TB SSD has 8GB of DRAM, but Samsung's trying to go one better.
Good insight. Is it some sort of ratio, like 2GB per 1TB or something? Or just moar = better?
There is a minimum level for holding the entirety of both maps, but I'm buggered if I can find it on Google. I want to say a gigabyte per terabyte, but I don't know if that's just because my brain likes round figures and made it up. You can get away with less, of course, and only have the part of the map you're currently using in DRAM, and so-called DRAM-less SSDs (bet you can't guess why they're called that) just use the copies of the maps on the NAND flash (which makes things slow and, worse, means constant writes that push down the endurance of the drive considerably.)
Dunno about the exact minimum required, but 1GB per TB is certainly the rough rule Samsung has followed so far, for example the 15.36TB PM1633a has 16GB, the 2TB 960 Pro has 2GB while the 1TB 960 Pro has 1GB.
Yep it's just map data 99.9% sure from past reading (the cache/buffers are on the NAND chips or controller it self something like 64KB per NAND) as far as I am aware No user pending writing data is ever stored in the Dram it's for map use only
when your turning write caching off and on in windows that just means all writes are commited immediately (harms write speed a lot)
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