Isn’t QLC substantially slower than TLC, and because of the increased number of states to resolve for the cells, it’s a physical limitation - not a question of product segmentation or yield.
Yes. This is why you cannot make a small, fast pool out of it. The bandwidth/chip is lower, which is why you need >512GB to come close to exceeding 4GB/s.
I was under the impression that SLC has 100 times or more the write endurance of QLC, which would mean 64 GB would have several times more write endurance than an entire 1TB SLC drive. Even a small 16 GB SLC cache would have more, though I don't know the prices. Something like the Samsung 970 Evo has an SLC cache for it's TLC, but that might be more about write performance (less important for consoles) than write endurance. The case is less compelling for MLC, thinking about it.
You are right. I was a bit off on the SLC endurance. SLC right now costs ~$4/GB on the spot, and promises ~100000 writes per cell. So assuming 500-write endurance for the 1TB drive, you'd need ~5GB at ~20$ (currently) to match it. So there still is ~4x cost advantange for writes in SLC.
Could I ask about your figures for ""daily suspend of 32GB" is just 0.000007%"? I get different ones.
I should post less when tired. You are absolutely correct, a factor of 1000 snuck up there somehow.
It's really difficult to imagine a 2TB NVMe drive anywhere near $40 considering even Apple paid that much for 128GB of MMC in their iPhones last year. We're looking at 512GB being quite possible after the ongoing price drops, 1TB being optimistic and require a BOM compromise, and 2TB requiring a dramatic move beyond any sort of SSD supplier contract predictions.
Your pricing is way off. Even cheap eMMC costs more than what cheap flash does, 128GB is boutique and costs more/GB than even cheap eMMC. (on the spot, 128GB eMMC currently costs ~4 times as much per GB as the raw flash). Since this time last year, flash chip prices have fallen by more than half. Right now, the analyst predictions are that they will fall by more than half in the next 12 months. That is not the extreme prediction, that's the middle-of-the-road one.
The annoying part about pricing right now is that QLC does not have a readily available market price. It's going to be even cheaper, and whether or not 2TB is possible without major BOM compromises depends on just how low QLC will fall when there are multiple competitors.
I don't think this core flash storage will be replaceble. Sony hinted the performance of their storage solution "to exceed all NVMe solutions"; They might have integrated the storage controller in the main SOC, circumventing the 4 lane PCIe bottleneck. They could operate 8 NAND channels at ONFI 4 speeds (800MT/s), exceeding 6GB/s.
AMD will very soon ship PCIe 4.0. 4 lanes of that gives you ~8GB/s. PCI-E controllers are cheap, and NVMe is simply technically and operationally too good solution to pass up on. The only meaningfully wearable part being user-replaceable, and a commodity that you can buy anywhere just makes sense.
I think they can "beat anything available on the PC" while using the same interface. Firstly, because right now there are no PCIe 4.0 NVMe drives, so it's strictly truth in advertising (even though there will be such drives when PS5 launches), and secondly because they can plan the entire storage subsystem of their hardware and their os around having the ability to stream into memory at above 4GB/s, which is something that Windows probably won't do nearly as well even years after PS5 launches. Inefficiencies anywhere get amplified when the raw bandwidth goes up that much.
Dah-yum. Intel 660p QLC SSD. Nice and affordable and all, but the 1TB version has a total stated lifetime of 200 TB of writes.
Note that Intel is sandbagging a little there. The chips in that drive have a stated lifetime of 500 writes, but Intel has a reputation of their consumer drives being more reliable than advertised to watch out for, so they promised a lower number.
That or they're afraid write leveling will burn more than half of their write allotment...
