Experience of QLC drives - Be aware

sityeuropa

sityeuropa

sityeuropa

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I've started to swap out my Crucial P3 drives as the performance when you have filled them a little is very bad.
The more storage that is used on them thhe more this will diminish the write speeds. I don't know the exact numbers but when copying big files you will constantly hit bottlenecks.

After 250GB the transfer will drop to around 80MB sec

They are worse than a Crucial MX500 for copying large files.
 
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The issue is they use a portion of the available space as a cache operating in a faster mode (e.g. like earlier SLC or MLC based nand).

If either there is no capacity available to operate in this mode (because the drive is nearly full) then you will get slowdown.

Equally because this cache is only a limited amount, if you transfer significant amounts of data then this cache gets filled and is unable to recover leading to slower speeds.

Edit:
It's not unexpected behaviour and has been well documented
www.tomshardware.com

Crucial P3 SSD Review: Solid Secondary SSD

The P3 is an efficient budget drive with capacity to spare
www.tomshardware.com www.tomshardware.com
 
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I knew about the Cache but just just wasn't expecting the drops to be as low as 100 MB for single file transfers.
Probably did just assume with how old the MX500 SSD was and the jumps advertising GB/sec write speeds. Surely it wouldn't be as worse in that area than it.

Didn't know MX500 is TLC so I suppose it makes sense as they are still around £220 for 4tb.
 
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sityeuropa said:
I knew about the Cache but just just wasn't expecting the drops to be as low as 100 MB for single file transfers.
Probably did just assume with how old the MX500 SSD was and the jumps advertising GB/sec write speeds. Surely it wouldn't be as worse in that area than it.
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Unfortunately the cache on both QLC & TLC drives tends to hide how slow they really are, you definitely have to buy QLC carefully if you're doing very large file transfers.

sityeuropa said:
Didn't know MX500 is TLC so I suppose it makes sense as they are still around £220 for 4tb.
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The endurance on these drives is pretty low, the 2TB is 700 TBW and the 4TB is 1000 TBW, whereas Kingston's KC600 which uses similar hardware, but guaranteed TLC has 1200 TBW in the 2TB capacity and WD's Red SA500 has 2500 TBW in the 4TB capacity.

There have been rumours for awhile that Crucial use QLC in the MX500, at both 2TB and 4TB capacity and the low endurance and lack of specification (about which type of NAND they use) would support that theory. Though, admittedly the endurance on the P3 is significantly worse than the MX500, at just 440 TBW in 2TB capacity.
 
mattyfez said:
Yeah I have a Samsung QLC as a game/media storage drive it's absolutley fine, i'd get something better for a system drive, but its fine for storage.
Click to expand...

Same here, I use a Samsung SSD 870 QVO 8TB SATA as a second storage drive and knew about the massive speed drops of QLC if your continuously writing a large amount of data. But how often am I going to be writing about 78GB or so before it plummets to 160MB/s writes, certainly not that often and to be honest even if that size cache was on an OS NVMe drive, 99% of the time most people I bet wouldn't even notice because most will be reading data significantly more and not writing to it, so that cache will be emptied quick enough.

In the 20,980hrs this drive has be on (around 874 days) with 33.5TB written so far with 98% health still, less than five times that I can remember the cache even being filled in one go, once when I cloned a smaller drive over for the first time, and the rest copying games that exceed 80GB from my C: drive to the 8TB one. Unless your manipulating insane amounts of data on a daily basis QLC drives are perfectly fine even for an OS drive.

As for endurance, the capacity or a random death will most likely be a problem far before the drive will die of writes.
 
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Raiden85 said:
Same here, I use a Samsung SSD 870 QVO 8TB SATA as a second storage drive and knew about the massive speed drops of QLC if your continuously writing a large amount of data. But how often am I going to be writing about 78GB or so before it plummets to 160MB/s writes, certainly not that often and to be honest even if that size cache was on an OS NVMe drive, 99% of the time most people I bet wouldn't even notice because most will be reading data significantly more and not writing to it, so that cache will be emptied quick enough.

In the 20,980hrs this drive has be on (around 874 days) with 33.5TB written so far with 98% health still, less than five times that I can remember the cache even being filled in one go, once when I cloned a smaller drive over for the first time, and the rest copying games that exceed 80GB from my C: drive to the 8TB one. Unless your manipulating insane amounts of data on a daily basis QLC drives are perfectly fine even for an OS drive.

As for endurance, the capacity or a random death will most likely be a problem far before the drive will die of writes.
Click to expand...


Yeah sorry I misspelled it, Mines a samsung QVO, it just works and gives me no bother. OK if I try to clone the whole drive it will take a longer time, but I don't shift that much data that often so it doesn't matter to me.
 
I enabled "momentum cache" on my 2TB crucial MX500. it helps a bit. sends the crystaldiskmark scores thru the roof. although i know it has limitations, that system RAM caching trick they use is a nice feature. ;) mine is around 1 year old. time will tell how it travels. o/s and games, some other programs. 2 partitions.

I still like hdd's for backups as well. the newer ones ive found are an improvement in terms of noise at least.
i do like 'old' things that still work.
 
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last bsod i remember was an overclocking attempt circa 2018.
if anything now i underclock. undervolt. and thermally limit.
 
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