Review: Samsung SM951 256GB NVMe PCIe SSD
NVMe Takes the Performance Crown
Several weeks ago, I had the opportunity to review the Samsung SM951 512GB AHCI PCIe SSD. In the review, I noted that Samsung had originally told us that the SM951 would feature the NVMe protocol, but when it was launched earlier this year, it was only available with support for the AHCI protocol. Turns out, the Samsung SM951 is actually being manufactured in both AHCI and NVMe, but unfortunately for those looking for the NVMe SM951, Samsung’s initial production was limited to AHCI drives.
While the AHCI version of the Samsung SM951 is still one of the fastest client SSDs we’ve ever tested, the NVMe protocol’s software stack is significantly better suited for SSDs and, in turn, is expected to provide significantly better performance. Luckily, Samsung has started rolling out the first batches of the NVMe SM951 and they recently reached out to us with sample in hand for us to check out.
Samsung SM951 NVMe Specifications
| Manufacturer | Samsung | Samsung | Samsung |
|---|---|---|---|
| Model | SM951 NVMe | SM951 NVMe | SM951 NVMe |
| Model Number | MZVPV128HDGL-00000 | MZVPV256HDGL-00000 | MZVPV512HDGL-00000 |
| Form Factor | M.2 2280 | M.2 2280 | M.2 2280 |
| Capacity | 128GB | 256GB | 512GB |
| Controller | Samsung UBX (S4LN058A01) | Samsung UBX (S4LN058A01) | Samsung UBX (S4LN058A01) |
| NAND | Samsung 16nm Toggle Mode MLC | Samsung 16nm Toggle Mode MLC | Samsung 16nm Toggle Mode MLC |
| DRAM Cache | 256MB LPDDR2 | 512MB LPDDR2 | 512MB LPDDR2 |
| Sequential Reads | 2,000MB/s | 2,150MB/s | 2,150MB/s |
| Sequential Writes | 650MB/s | 1,260MB/s | 1,550MB/s |
| 4K Random Read | 300,000 | 300,000 | 300,000 |
| 4K Random Write | 83,000 | 100,000 | 100,000 |
| Interface | PCIe 3.0 x4 NVMe | PCIe 3.0 x4 NVMe | PCIe 3.0 x4 NVMe |
| Warranty | N/A | N/A | N/A |
The Samsung SM951 NVMe will be available in capacities of 128GB, 256GB, and 512GB. The drives will come in the M.2 2280 form factor and natively supports a PCIe Gen 3 x4 interface along with the NVMe protocol. Just like the AHCI Samsung SM951 SSD, the NVMe Samsung SM951 will be available to OEMs only.
The Samsung SM951 NVMe’s onboard components are identical to the Samsung SM951 AHCI, so we’re looking at Samsung’s in-house UBX controller paired with Samsung 16nm Toggle Mode MLC. Samsung is expected to switch to newer 3D V-NAND and higher capacities down the line, but no official timeframe has been revealed at this time.
Sequential read/write performance is slightly faster than what we saw with the specs of the SM951 AHCI SSD with performance up to 2,150MB/s sequential reads and 1,550MB/s sequential writes. 4K random read performance is rated at up to 300,000 IOPS and 4K random write performance is rated at up to 100,000 IOPS for the higher capacities.
Let’s take a closer look!
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