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Samsung SM951-NVMe Versus AHCI Versus SATA 850 Pro

PCMark 8 Advanced Workload

To learn how we test advanced workload performance, please click here.

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The PCMark 8 workload tests use the same data as PCMark 8's real-world benchmarks, but run the modules back to back after preconditioning the drives. After steady state is achieved, time is added between runs to allow the wear-leveling algorithms to recover performance. 

We've already mentioned that Samsung SSDs are not as aggressive as some others, so the clean-up time takes longer. Since we're only comparing Samsung products, we don't need to compare the company's wear-leveling to its competition. We will say, however, that Samsung's drives would deliver higher performance in the recovery phase of this test if the five-minute pause between runs was longer. Performance would also improve if Samsung over-provisioned its SSDs. As they sit from the factory, all three drives give you the full LBA span to store data. Of course, you're able to configure these 256GB models with 240GB of user space and 16GB allocated for background activities during the format process.

The throughput results show what we expected after seeing the PCMark 8 real-world results. Again, these three drives behave nearly the same under identical load levels due to their underlying architecture. The difference in performance is clear, though.

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The service times show us how long each test iteration takes to complete all of the tasks. The 256GB SM951s deviate less than the 850 Pro 256GB when measuring heavy and light workloads. Most desktop users should focus more on the recovery portion for an indication of daily use performance though, while professional users running write-intensive workstation applications should focus on the middle steady state area.

The SM951 products were designed to provide superior performance for professional users. What makes them so attractive for everyone is their low latency during the recovery phase. Samsung didn't really design the SM951 for light workloads; its success there is just a byproduct of making very good workstation SSDs.

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