Mixed Random Read/Write Performance

Most real-world use consists of a mix of reads and writes, and interleaving the two often poses a particular challenge to drive controllers. This mixed random access test is conducted across a 16GB span of the drive, but on a full drive and with a queue depth of 3.

Iometer - Mixed 4KB Random Read/Write

Mixed random access seems much improved over Samsung's earlier M.2 drives, and the 950 Pros fall behind only the Intel SSD 750. The 512GB drive is well behaved here and surpassing the 256GB drive as it should.

Iometer - Mixed 4KB Random Read/Write (Power)

In this case, the higher power consumption of the 950 Pro is very well justified by the higher performance.

Samsung 950 Pro 256GB

There's not much variation across the different workloads. Performance hardly drops during the middle of the test where many controllers have trouble with a balanced mix, but on the other hand the performance at either end of the test is nothing spectacular. Power consumption climbs hand in hand with the proportion of writes, but is accompanied by some increasing in overall data rate.

Mixed Sequential Read/Write Performance

The queue depth of 3 is sufficient for many drives to perform very well at either end of this test, while testing 100% reads or 100% writes. In between, performance typically suffers greatly, and that's where the winners and losers of this test are determined. Anything that's duplicating duplicating or transforming a large amount of data on the drive will produce I/O patterns similar to this test. Creating a System Restore snapshot, backing up files to a different directory on the same drive, and file compression can all produce interleaved reads and writes of large blocks of data, though not necessarily fast enough to be limited by the drive's performance.

Iometer - Mixed 128KB Sequential Read/Write

These sequential workloads allow the PCIe drives to stand out and achieve average speeds that would saturate SATA.

Iometer - Mixed 128KB Sequential Read/Write (Power)

With power consumption in the same neighborhood as the SATA drives, the 950 Pro is significantly more efficient.

Samsung 950 Pro 256GB

Looking at the breakdown by workload, the 950 Pro performs well on the balanced mixes and far outstrips the SATA limit on the very read-heavy workloads and the pure write section at the end of this test.

Sequential Performance Idle Power Consumption & TRIM Validation
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  • Gigaplex - Thursday, October 22, 2015 - link

    What you're proposing isn't actually booting the drive. It's chainloading. The assessment is accurate, and chainloading is a long standing practice for this type of problem. It's also a hack that has no business being used for general consumer usage.
  • R3MF - Thursday, October 22, 2015 - link

    does the supplied samsung driver work with Win7, and is its use as simple as pointing the windows installer to a USB thumbdrive at the appropriate point?
  • Billy Tallis - Thursday, October 22, 2015 - link

    The Samsung NVMe driver was provided as an installer program. After running the installer, there was no need to explicitly change which NVMe driver was used for the 950 Pro. I tested it on Windows 7, 8.1, and 10.
  • Badelhas - Thursday, October 22, 2015 - link

    I have a Vertex 3 128GB SSD. Do you guys believe I will see real world gains if I upgrade to the Samsung 950 Pro 256GB?
  • MrSpadge - Thursday, October 22, 2015 - link

    If your usage is "normal" for a desktop, I suspect "no" is the answer. Unless you're doing a side-by-side comparison. Watch the disk drive LED on your machine. If it's glowing constantly you're being limited by the storage, otherwise not. Or look at the drive load in task manager (shown since Win 8).
  • III-V - Thursday, October 22, 2015 - link

    >For starters, the 950 Pro's power consumption increases as it heats up, and I've seen its idle power climb by as much as 4.5% from power on to equilibrium.

    Er, yeah, that's how typical transistors work... they get leakier as they heat up :\
  • boogerlad - Thursday, October 22, 2015 - link

    What is the latency difference between having this ssd connected directly to the cpu, and through the pch? I'm very curious but no one has tested this.
  • TelstarTOS - Thursday, October 22, 2015 - link

    Performance is a bit of a mixed bag, but price/perf ratio is great.
    Waiting for intel countermove now :)
  • DIYEyal - Thursday, October 22, 2015 - link

    Does it suffer from similar thermal throttling issues as it's predecessors (SM951 and XP941)? I have seen people putting a heat sink on these and they report improvement in sustained performance.
  • theMillen - Saturday, October 24, 2015 - link

    http://www.legitreviews.com/samsung-ssd-950-pro-51... will answer any heat throttling questions you have, ie yes! but a simple fan solves them :-p

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