[Gen3] Choosing between Crucial P3 vs Samsung 980 as my secondary(1TB)?

[pratikbiska]

Need help choosing between these ssds:

Crucial P3 1TB PCIe 3.0 NVMe M.2 2280 SSD - CT1000P3SSD8
Samsung 980 1TB PCIe 3.0 NVMe M.2 SSD - MZ-V8V1T0BW
I'm choosing these as these are within my budget.

Whilst researching, I found conflicting/confusing information about which one is better.

Is it true that Crucial uses a QLC while Samsung uses TLC NAND? or am i wrong?

 

 

[mariushm]

Samsung 980 uses TLC memory (128 layer v-nand).  It does 3.5 GB/s read, 3 GB/s write, and has a write endurance of 600 TB.

Crucial P3 uses QLC memory (176 layer) . It does the same speeds but has a write endurance of 220 TB (for the 1 TB version)

 

Samsung 980 can use up to around 160-200 GB (on the 1 TB model) of memory in pseudo-SLC cache (where you get faster write speeds and higher endurance) as a write cache. Once that amount is filled, the write speeds drop to around 300 MB/s 

In the first picture below, the 500 GB version of Samsung 980 can be seen in red ... around 100 GB are written at ~ 2.5 GB/s and then as the pSQL write cache gets full, speeds drop to ~300 MB/s

Once the high speed transfer is done and the drive is idle, the cache recovers at around 30 GB per minute (the controller moves data to permanent tlc memory while idle)

 

 

 

 

The Crucial P3  can use ALL the QLC memory in pSLC mode, so the more empty space you have the more can be used in pSLC mode as write cache. 

Basically, whatever free space there is,  divide it by four and that's the pSLC memory. 

On the 2 TB model reviewed by Tom's hardware, you can see in the picture below in red, how it could write around 550 GB of content at around 3.2 GB/s and then the sLC cache got full and the drive had to start converting some of this pSLC memory back into QLC .. so the controller alternates between converting to TLC, accepting more data, converting to TLC and so on... so you get the speeds like in the chart below ... less than 100 MB/s for some time, then a burst of 1-1.5 GB/s, then again less than 100 MB/s 

 

When the drive is fairly empty, it's ok, as you're never going to write 250 GB at a time (which would be the amount of pSLC for a 1 TB model) but it gets worse the more the drive gets full...

For example let's say for example you use 800 GB out of 1 TB and you want to install a 60 GB game. There's only 200 GB empty, so only around 40 GB of pSLC write cache ... you install the 50 GB game and the first 40 GB get installed in 10-15 seconds and then the other 10 will take a couple minutes at 100 MB/s 

 

 

 

[Wooden Law - Black]

Yeah it's true, the P3 uses Micron QLC flash whereas the 980 Samsung TLC one. Thanks to the better flash the 980 performs better and has a longer endurance than the P3, but I would choose this latter if the usage is as secondary drive and if it's a lot cheaper. 

[pratikbiska]

On 11/24/2022 at 4:29 PM, Wooden Law - Black said:

Yeah it's true, the P3 uses Micron QLC flash whereas the 980 Samsung TLC one. Thanks to the better flash the 980 performs better and has a longer endurance than the P3, but I would choose this latter if the usage is as secondary drive and if it's a lot cheaper. 

It's about $77 for P3 and $80 for the Samsung one. So Samsung I guess?

[pratikbiska]

On 11/24/2022 at 4:29 PM, mariushm said:

Samsung 980 uses TLC memory (128 layer v-nand).  It does 3.5 GB/s read, 3 GB/s write, and has a write endurance of 600 TB.

Crucial P3 uses QLC memory (176 layer) . It does the same speeds but has a write endurance of 220 TB (for the 1 TB version)

 

Samsung 980 can use up to around 160-200 GB (on the 1 TB model) of memory in pseudo-SLC cache (where you get faster write speeds and higher endurance) as a write cache. Once that amount is filled, the write speeds drop to around 300 MB/s 

In the first picture below, the 500 GB version of Samsung 980 can be seen in red ... around 100 GB are written at ~ 2.5 GB/s and then as the pSQL write cache gets full, speeds drop to ~300 MB/s

Once the high speed transfer is done and the drive is idle, the cache recovers at around 30 GB per minute (the controller moves data to permanent tlc memory while idle)

 

 

 

 

The Crucial P3  can use ALL the QLC memory in pSLC mode, so the more empty space you have the more can be used in pSLC mode as write cache. 

Basically, whatever free space there is,  divide it by four and that's the pSLC memory. 

On the 2 TB model reviewed by Tom's hardware, you can see in the picture below in red, how it could write around 550 GB of content at around 3.2 GB/s and then the sLC cache got full and the drive had to start converting some of this pSLC memory back into QLC .. so the controller alternates between converting to TLC, accepting more data, converting to TLC and so on... so you get the speeds like in the chart below ... less than 100 MB/s for some time, then a burst of 1-1.5 GB/s, then again less than 100 MB/s 

 

When the drive is fairly empty, it's ok, as you're never going to write 250 GB at a time (which would be the amount of pSLC for a 1 TB model) but it gets worse the more the drive gets full...

For example let's say for example you use 800 GB out of 1 TB and you want to install a 60 GB game. There's only 200 GB empty, so only around 40 GB of pSLC write cache ... you install the 50 GB game and the first 40 GB get installed in 10-15 seconds and then the other 10 will take a couple minutes at 100 MB/s 

 

 

 

Sooooo....... Which one?

[Wooden Law - Black]

Samsung.