Hector Martin

Have a QLC drive here as well (Samsung QVO), it warms up quickly at full load, and throttles it's speed down sharply once it reaches a specific temperature. QLC drives do not seem suitable for constant load, more applicable to burst loads.

Most M.2 drives warm up very quickly, need to buy a heatsink for them

"ExplainingComputers" on youtube looked a little into this. Samsung QLC drives appear to use SLC cache of around 36GB, so up until 36GB performance was exactly the same as TLC (rather simplistic test, just transferring files), throughput then dropped to 70mb/s on QLC

Cool story. I'll tell that to my qlc drive that's been doing just fine since I got it. Not all people have the same use cases.

If you have a read-mostly workload then it's probably fine. If you ever wind up having to do sustained writes and relying on performance not being terribad, you'll regret using QLC. At least the crucial ones fall over *badly*, not just "really slow" but pathologically slow.

Got a detailed writeup on your findings somewhere? This *really* much sounds like a bad controller design problem (not itself caused by the number of bits per cell, but by the way they are reconstructed on reading, or maybe how they are written), and that'd be where suppliers 1/2

Firmware is definitely part of the problem (especially the 1 second latencies), but QLC flash having terrible performance (hidden by a TLC/MLC buffer that fills up quickly) is a thing.