Samsung SM961 MZ-VPW2560

[ned14]

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https://github.com/geerlingguy/raspberry-pi-pcie-devices/issues/647 reports that the SM961 doesn't work, however I did not find this myself with the latest eeprom:

rpi-eeprom-update
BOOTLOADER: up to date
   CURRENT: Tue Jan 14 00:16:48 UTC 2025 (1736813808)
    LATEST: Tue Jan 14 00:16:48 UTC 2025 (1736813808)
   RELEASE: beta (/lib/firmware/raspberrypi/bootloader-2712/beta)
            Use raspi-config to change the release.

The SM961 works absolutely fine in both PCIe 2.0 and PCIe 3.0 on two M.2 adapters I tried. Mine came from eBay for €16 and was heavily used, but still has years of lifespan left in it. It has an inhouse Samsung manufactured controller with Samsung flash and I think it has DRAM, which makes it especially speedy under random i/o on the Pi:

https://www.techpowerup.com/ssd-specs/samsung-sm961-512-gb.d1214

This is running at PCIe 2.0:

dd if=/dev/zero of=/dev/nvme0n1 bs=1M count=10000 oflag=direct
10485760000 bytes (10 GB, 9.8 GiB) copied, 28.1119 s, 373 MB/s

Idle is 0.3 watts, write load is +3 watts.

dd of=/dev/null if=/dev/nvme0n1 bs=1M count=10000 iflag=direct
10485760000 bytes (10 GB, 9.8 GiB) copied, 24.0549 s, 436 MB/s

Idle is 0.3 watts, read load is +3 watts.

This is running at PCIe 3.0:

dd if=/dev/zero of=/dev/nvme0n1 bs=1M count=10000 oflag=direct
10485760000 bytes (10 GB, 9.8 GiB) copied, 15.1569 s, 692 MB/s

Idle is 0.3 watts, write load is +3.6 watts.

dd of=/dev/null if=/dev/nvme0n1 bs=1M count=10000 iflag=direct
10485760000 bytes (10 GB, 9.8 GiB) copied, 12.6483 s, 829 MB/s

Idle is 0.3 watts, read load is +3.3 watts.

I've given this drive a sound battering with constant i/o load over a week at PCIe 3.0 speeds and there have been zero errors or anything in the Linux kernel log. Good drive, and great value for €16.