QLC drives can't take advantage of PCIe 4.0, and because of the extra costs of making this drive PCIe 4.0, it's way too expensive, period.
I would consider QLC if it was both big (so 4TB or more) and at least 20% cheaper per TB than the cheapest TLC drive. I'm not taking the performance or endurance hit of QLC without the accompanying decrease in costs. It is inferior and anyone paying more for it is being conned. If 10c/GB is the price of decent budget drives, QLC cannot cost more than 8c/GB and even then I think I'd rather just pay the extra for TLC's performance consistency and endurance. At least at 8c/GB I'd consider QLC for some applications; Right now it's a hard no.
Part of me also wonders if direct writes to QLC wouldn't be quite so abysmal if they didn't use ALL available space as an SLC cache. If even 10% of the free space was reserved as QLC to stream direct writes to in the event of the SLC cache being full, the drive wouldn't be trying to handle an incoming stream of data from the host whilst also running garbage collection AND reading from SLC AND writing to QLC-mode NAND all at the same time.
Cheap TLC drives like the WD SN550 aren't going to set the world on fire, but they're fast enough all of the time. Never will your performance drop so low that you'd be better off using a mechanical drive. Isn't that the point of SSDs? To be better than a mechanical drive?
