After shipping two generations of M.2 drives with PCIe interfaces for OEM customers, Samsung is releasing a PCIe drive to the retail market which has the added benefit of including the latest features Samsung offers. The Samsung 950 Pro is the new flagship consumer drive and it eschews the backwards compatibility and the 2.5" SATA form factor of the three previous iterations of the 8xx Pro family in favor of a PCI Express 3.0 x4 connection in the M.2 2280 form factor coupled with the NVMe protocol. Those changes allow for one of the biggest generational performance jumps in the history of the SSD industry and should help the transition of SSDs shedding the last vestiges and limited feature sets of their mechanical hard drive predecessors.

The M.2 2280 form factor has the potential to unify the consumer SSD market, with a physical size small enough for ultrabooks but a large enough capacity for all users. M.2, depending on the exact implementation used by the OEM, has the ability to provide SATA or high-performance PCIe connectivity, easing the transition. By supporting up to four lanes of PCIe 3.0, M.2 has helped make the two-lane SATA Express standard dead on arrival and ensures that drives won't be starving for bandwidth again for quite some time.

Meanwhile, high-end SSDs have been struggling to squeeze every last drop of performance out of the 6Gb/s SATA III interface. While some vendors have put out M.2 PCIe devices that support two lanes of PCIe, Samsung went straight for four lanes with the XP941 drive for OEMs to start. This was then upgraded to PCIe 3.0 speeds with the SM951. Earlier this year, they implemented the NVMe protocol which allows the SM951 to make use of the available bandwidth of the PCIe 3.0 x4 link. With Intel's Skylake platform bringing plentiful I/O bandwidth to support multiple lanes of PCIe 3.0 to more than just the graphics card, a good number of external bottlenecks are bypassed and Samsung can stretch the true capabilities of the hardware. This is a main focus of the 950 Pro.

Samsung SSD Comparison
  950 Pro
950 Pro
SM951-NVMe 512GB (OEM) 850 Pro
Form Factor M.2 2280 2.5" SATA
Controller Samsung UBX Samsung MEX
Interface PCIe 3.0 x4 SATA III
Protocol NVMe AHCI
DRAM 512MB 512MB 512MB
NAND Samsung V-NAND 32-layer 128Gbit MLC Samsung 16nm 64Gbit MLC Samsung V-NAND 32-layer 86Gbit MLC
Sequential Read 2,500MB/s 2,200MB/s 2,150MB/s 550MB/s
Sequential Write 1500MB/s 900MB/s 1,550MB/s 520MB/s
4KB Random Read (QD32) 300K IOPS 270K IOPS 300K IOPS 100K IOPS
4KB Random Write (QD32) 110K IOPS 85K IOPS 100K IOPS 90K IOPS
Power 7.0W (burst)
5.7W (average)
1.7W (idle)
6.4W (burst)
5.1 (average)
1.7W (idle)
8.9W (peak) 3.3W (read)
3.0W (write)
0.4W (idle)
Encryption AES-256, TCG Opal 2.0 N/A AES-256, TCG Opal 2.0
Endurance 400TB 200TB N/A 300TB
Warranty 5 Year N/A 10 Year
Launch Date October 2015 ~June 2015 July 2014

The 950 Pro is using the same UBX controller as the SM951, but pairs it for the first time with 3D NAND. We first saw Samsung's 128Gb 32-layer V-NAND in the 2TB 850 Pro, introduced about a year after the original 850 Pro. None of the major components of the 950 Pro are entirely new, but this is the first consumer level product to combine them. The 950 Pro is an aggressive push forward; it's a bit risky to be bringing so much new tech in one product to the unforgiving retail market. Samsung will bear the brunt of any immaturity or incompatibilities, but they are hoping to lead the way for a much broader shift in the market.

PCI Express has been around for a long time and offers forward and backward compatibility, but until very recently most systems only offered 16 lanes from the processor, mainly for graphics cards, and one-lane slots for anything else from the chipset. With Intel's Haswell generation of processors the SATA Express connector and M.2 slot started appearing, but systems with a four-lane PCIe 3.0 connection available (and with enough overall bandwidth to fully feed it) are still quite rare. As a result, most consumers could only get that much bandwidth from one of their graphics card slots, moving any discrete graphics card to half PCIe bandwidth. This changes with Skylake and the 100-series chipsets that can support 20 PCIe 3.0 lanes of connectivity through the chipset, and up to three PCIe 3.0 x4 drives in Intel's RST mode for RAID combinations.

The 950 Pro is the new flagship, but it is certainly not a replacement for the 850 Pro. The pricing reflects that: $200 MSRP for the 256GB and $350 for the 512GB is about 50% higher than current retail prices for the 850 Pro, which is still one of the top performing consumer SSDs. Samsung is betting that the market is ready for a new premium category that's meant to be a part of the newest and fastest machines.

The 850 Pro will be sticking around in its current role, and as it's refreshed to use the 128Gb V-NAND the range of capacities will expand further, with a 4TB model of the 2.5-inch drive due in early 2016. The switch to 128Gb V-NAND may also allow prices to drop and widen the gap between the 850 Pro and the 950 Pro.

AnandTech 2015 SSD Test System
CPU Intel Core i7-4770K running at 3.5GHz (Turbo & EIST enabled, C-states disabled)
Motherboard ASUS Z97 Deluxe (BIOS 2501)
Chipset Intel Z97
Chipset Drivers Intel 10.0.24+ Intel RST
Memory Corsair Vengeance DDR3-1866 2x8GB (9-10-9-27 2T)
Graphics Intel HD Graphics 4600
Graphics Drivers
Desktop Resolution 1920 x 1200
OS Windows 8.1 x64
Testing With NVMe Over PCIe


View All Comments

  • Per Hansson - Wednesday, October 28, 2015 - link

    If you really need it FXi there is always the announced Samsung SM953 drive.
    It's 110mm long due to the inclusion of the tantalum capacitors, otherwise it's very similar to the SM951...
  • R3MF - Sunday, October 25, 2015 - link

    i was under the impression that win7 (install disk) does not support nvme, so i'm curious as to how you went about getting Win7 on a 950? Reply
  • Kristian Vättö - Sunday, October 25, 2015 - link

    There is a hotfix NVMe driver available for Windows 7: Reply
  • blos - Monday, October 26, 2015 - link

    I slipstreamed that hotfix (and almost 200 other fixes) using NTLite to a Win7SP1 image, wrote it back to usb, booted and it would still not allow me to install to a 951 NVMe drive... no drives found.

    Has anybody got this to work?

    Windows 10 installs just fine but I have an unused W7 Pro license and I would really like to use it to active a W10 install.

    I hear the next version of W10 will activate directly from W7 licenses... but hopefully that'll arrive in time before the W10 will really want the activation. Or perhaps re-arming to extend a bit?
  • Per Hansson - Wednesday, October 28, 2015 - link

    Yes it works but you need to integrate it in boot.wim as well.
    I made some details here about it, also nothing an errors that MS is still to fix in that KB article.
    Even though I reported it a long time ago:
  • blos - Wednesday, October 28, 2015 - link

    Ah that explains a lot, didn't know that the boot.wim was a different environment :)

    Quick search indicates that boot.wim integration is already available on the NTLite, so I guess it's playtime for this weekend :)
  • catavalon21 - Wednesday, October 28, 2015 - link

    The test system doesn't have a discrete video card. Would a high-powered video card impact the performance of the M.2 PCIe setup? Reply
  • AnnonymousCoward - Wednesday, October 28, 2015 - link

    No. Reply
  • Caramonn - Friday, October 30, 2015 - link

    I've read the review and others and I guess I don't see a reason to get one of these drives yet. Am I missing something? It seems that the real world performance doesn't justify the nearly twice the cost as other Samsung SATA drives. I was really hoping that the rated speeds would translate into actual real world performance, but that doesn't appear to be the case. Reply
  • Tuishimi - Thursday, November 5, 2015 - link

    $350... I could live with that. Sounds like a decent piece of hardware. Reply

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