New m.2 Samsung NVMe SSD outed by HP!

HP Z Turbo Drive Zoomed - wrong SSD
HP Z Turbo Drive Zoomed - wrong SSD

Today we have evidence of a new m.2 Samsung NVMe SSD. This new NVMe SSD should come in both 256GB and 512GB versions. When the Samsung XP941 came out we finally had a low power and low cost m.2 PCIe SSD that was capable of delivering very strong performance. The Samsung SM951 is its successor providing faster speeds due to the PCIe 3.0 interface. Both drives were really meant to be OEM only or at least OEM only for some time before a few may make it into retail channels. Neither drive was NVMe based and NVMe is the (near) future of performance SSD storage.

HP used its market power as a leading OEM to build an interesting card, the HP Z Turbo Drive. The initial HP Z Turbo Drive bundled the Samsung XP941 with a m.2 to PCIe converter card. This is similar to the setup we used for XP941 256GB and 512GB quick benchmarks. One can now find the new HP Z Turbo Drive G2 product on HP’s website. Here is the product information PDF. The specs for the drive simply do not add up to what we have seen thus far. We see from that product sheet that the HP Z Turbo Drive G2 is a NVMe based part based on the last paragraph of text from page 1 of the HP file linked above:

HP Z Turbo Drive G2 NVMe
HP Z Turbo Drive G2 NVMe

One can see the Samsung XP941 part number MZHPU256HCGL-00H1 branding in the product shot on page 1 of the PDF. Here is a zoomed in version:

HP Z Turbo Drive Zoomed - wrong SSD
HP Z Turbo Drive Zoomed – wrong SSD

However, the Samsung XP941 (256GB version pictured above) was not a NVMe SSD. The newer Samsung SM951 is also not a NVMe SSD (AHCI instead) so we have something different based on the specs we are seeing.

When we review the specs of the Samsung SM951 we can see fairly standard 4K IOPS numbers:

Samsung SM951 Specs
Samsung SM951 Specs

When we look at the HP Z Turbo Drive G2 specs, we see a significantly faster drive:

HP Z Turbo Drive G2 Datasheet zoom
HP Z Turbo Drive G2 Datasheet zoom

Samsung NVMe SSD read speeds are the same as the SM951 256GB and 512GB drives. Write speeds increase by 60MB/s and 50MB/s for the versions respectively. The 4K random read IOPS go from 90K on the SM951 series to 300K on the HP Z Turbo Drive G2. That is more than a 3x improvement! The 4K random write IOPS increase from 70K to 100K which is not as large of a gain but is still significant.

It is rumored that Samsung was originally intending the SM951 to be a NVMe drive but that support was dripped. This may be a new version of the drive with NVMe support and the first client focused Samsung NVMe SSD.

We still do not have street pricing but it is likely we will see the Intel 750 SSD put pressure on this offering to bring prices closer to the $1/ GB range excluding HP support and warranty. We can see from a saved ebay search here that the street pricing of the XP941 based HP Z Turbo Drive (first generation) was closer to $1.6/ GB or more.

One other nice point, while the SM951 has had rumored endurance ratings, this new Samsung NVMe SSD (m.2) is rated at 146TB for the 256GB variant and 292TB for the 512GB variant.

We await more on the drive, but the NVMe era is quickly arriving for lower end devices.


  1. STH does it again. I would have thought it was a SM951 if it wasn’t for this. Nice investigation team STH

  2. The SM951 can hit the same IOPS numbers at high queue depths. I never published my 128 and 256 QD numbers.

    The Lenovo drives were also limited by the firmware. I think it was to save power. I have fresh drives here that reach 2150 MB/s seq read and 1650 write. These are still the AHCI drives, just not Lenovo models.


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