Librem 15 Storage Options

Hardware
1

The buying page for Librem 15 gives two storage options:

  • Storage (M.2 SSD)
  • Storage (2.5" SATA 3 SSD)

Questions:

  1. What is the difference?
  2. What is the advantage of one over the other
  3. If money was no object, would it be advantageous to get both?
2

M.2 SATA SSD and 2.5 SATA SSD are just two different formats with the same performance the benefit of both would be more storage.

M.2 NVMe SSD is faster than the other two. If you got both an M.2 NVMe SSD drive and a 2.5 SATA SSD the generally “better” setup would be M.2 NVMe SSD for boot and other things you want higher performance from and the 2.5 SATA SSD for additional storage.

Last time I checked the M.2 drop-down offered both SATA and NVMe drive so that may be worth keeping an eye on.

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3

That’s an understatement. On current hardware an NVMe SSD is up to 7 times faster than a SATA III SSD. So if money is no object (ha ha) then you would get the 1TB NVMe Pro SSD - and you would put your operating system on it and anything else that you want to be as fast as possible.

In the real world where money is an object, you would then also get the SATA III SSD as big as you need in order to put everything else on it (under the assumption that 1TB is not enough).

On the order screen, hovering over the blue question mark next to the chosen storage option will bring up the manufacturer’s claimed read and write speeds for the drive. (The order page does not say what PCIe version and number of lanes are available to the M.2 drive but if those speeds are to be achieved then it would be PCIe 3.0x4, or better.)

Everything of course depends on what the intended use for the laptop is. You might not need a second drive at all. You might not need 1TB. You might be happy with the speed of a vanilla SATA III SSD (which is still way better than a spinning disk).

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4

sata 3 interface is up to 6 gb/s (expressed in MegaBytes that would be 6000mb/8 or aprox 750 MB/s)
because a byte is 8 bits
pcie x4 nvme is up to 32gb/s (expressed in MegaBytes that would be 32000mb/8 or aprox 4000 MB/s)

if you sequentially read and write data at the same time on the storage medium you will likely not get more than the above (speaking in an idealized manner)

however the true performance gains for using ssd as bootable drives comes from the qdepth performance.
this is where the most expensive ssds keep the cake and eat it at the same time because latency (access time) matters more than sequential speeds for the OS.

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5

Those are theoretical bus / interface speeds though, not claimed drive speeds (never mind about measured drive speeds).

It is not unusual to see SATA III SSDs claiming read speeds of around 550MB/s and that is more or less achievable. I don’t think I have ever seen one claim close to 750 MB/s.

Sadly money is an object :slight_smile: and I don’t have the latest, best hardware but I have measured NVMe speeds over 2000 MB/s. So that’s around four times faster than SATA III already. Current hardware should do even better.

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