The Samsung 950 Pro PCIe SSD Review (256GB and 512GB)

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.

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.

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

Samsung 950 Pro 256GBSamsung 950 Pro 512GBSamsung 850 Pro 2TBSamsung 850 EVO 2TBADATA XPG SX930 120GBADATA XPG SX930 240GBADATA XPG SX930 480GBCorsair Neutron XT 480GBCrucial BX100 120GBCrucial BX100 250GBCrucial BX100 500GBCrucial BX100 1TBCrucial MX100 512GBCrucial MX200 250GBCrucial MX200 500GBCrucial MX200 1TBJMicron JMF670H 120GBJMicron JMF670H 240GBJMicron JMF670H 480GBOCZ Trion 100 240GBOCZ Trion 100 480GBOCZ Trion 100 960GBOCZ ARC 100 240GBOCZ Vector 180 240GBOCZ Vector 180 480GBOCZ Vector 180 960GBSamsung 850 EVO M.2 120GBSamsung 850 EVO mSATA 250GBSamsung 850 EVO M.2 500GBSamsung 850 EVO mSATA 1TBSamsung 850 EVO 1TBSamsung SSD 850 Pro 512GBSanDisk Extreme Pro 480GBSanDisk Ultra II 240GBSMI 2256 Reference Design 500GB

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.

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

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

Samsung 950 Pro 256GBSamsung 950 Pro 512GBSamsung 850 Pro 2TBSamsung 850 EVO 2TBADATA XPG SX930 120GBADATA XPG SX930 240GBADATA XPG SX930 480GBCorsair Neutron XT 480GBCrucial BX100 120GBCrucial BX100 250GBCrucial BX100 500GBCrucial BX100 1TBCrucial MX100 512GBCrucial MX200 250GBCrucial MX200 500GBCrucial MX200 1TBJMicron JMF670H 120GBJMicron JMF670H 240GBJMicron JMF670H 480GBOCZ Trion 100 240GBOCZ Trion 100 480GBOCZ Trion 100 960GBOCZ ARC 100 240GBOCZ Vector 180 240GBOCZ Vector 180 480GBOCZ Vector 180 960GBSamsung 850 EVO M.2 120GBSamsung 850 EVO mSATA 250GBSamsung 850 EVO M.2 500GBSamsung 850 EVO mSATA 1TBSamsung 850 EVO 1TBSamsung SSD 850 Pro 512GBSanDisk Extreme Pro 480GBSanDisk Ultra II 240GBSMI 2256 Reference Design 500GB

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.