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Samsung SM951 PCIe M.2 512GB SSD Review

Samsung introduced the SM951 last July during its annual SSD Global Summit in South Korea. Today we're running the drive through our benchmark suite to see if it lives up to the hype.

PCMark 8 Advanced Workload Performance

Futuremark created what we consider to be the best SSD benchmark to date. It shows both heavy and light use over time. The advanced disk tests run from a command line interface, preconditioning the drives before simulating heavy workloads. After the steady state heavy workload metrics finish, five-minute intervals fit between each test, allowing the device under test to recover through background activity with garbage collection, TRIM and wear leveling. This simulates typical consumer workloads that we experience everyday. 

Throughput Tests

The three drives on our chart make analysis easy, since performance varies by a wide margin.

Even under heavy workloads, the SM951 512GB is significantly faster than than the other two PCIe-based SSDs we benchmarked.

For most users, the light workload tests better resemble real-world conditions experienced on a daily basis. What surprises us is the large difference between the highest-performing Samsung SM951 and Plextor's last-place M6e Black Edition 512GB.

Latency Tests

Low latency is what makes your computer feel responsive. This is why systems equipped with SSDs are so much faster than those with mechanical disks. Hard drives are bottlenecked by heads and platters moving around, while SSDs can jump to the next transaction without that wait.

This is the first chart in our review where Samsung's latest is beaten by another SSD. The SM951 delivers higher throughput, but at the same time exposes us to higher latency.

The difference between the XP941 and SM951 is so small that it's almost negligible. Both Samsung SSDs deliver lower latencies than a majority of SATA-based drives. Unfortunately, Plextor's M6e Black Edition lands well above the latency levels we expect from a premium SSD in 2015. 

Chris Ramseyer is a Contributing Editor for Tom's Hardware US. He tests and reviews consumer storage.