07-15-2015, 09:07 PM
Here's what I am talking about:
Quote:We were surprised to see the 850 Evo 2TB outperform the 850 Pro 2TB in this series of tests. Unlike the previous benchmark results from PCMark 8, these run under more demanding conditions, with less time between each metric. They aren't enterprise-oriented, but come close to that level of load.
Normally we see the SanDisk Extreme Pro 1TB dominate this discipline, with the 850 Pro 1TB close behind. Under the lighter workloads, we expect the 850 Pro 2TB to outperform the smaller 1TB model. However, it just couldn't recover fast enough to climb back.
We would normally suspect a TRIM issue. But the 850 Evo recovered well and led the light workload portion of the test.
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The latency numbers show us where the 850 Pro 2TB falls short and where the 850 Evo 2TB turns into a beast. Under heavy load, Samsung's 850 Pro 2TB took nearly twice as long to complete the tests as the 850 Pro 1TB. When the drives are given time to recover, the 850 Pro 2TB fails to clean the NAND or direct the data writes to clean flash. This is something Samsung will need to look into and fix in a future firmware update.
The 850 Evo 2TB performs better than we expected under demanding conditions, and then brings the service times down to class-leading levels when it's given time to recover.
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We spent a lot of time exploring the 850 Pro 2TB performance abnormality we found, but not enough to isolate the problem. This is a bad time for Samsung to have firmware issues. Some users are still reporting slow-downs on the 840 Evo, even after the company attempted multiple fixes. The 840 Evo is the best-selling client SSD of all time. But the transition to three-bit-per-cell flash may have come too soon or without powerful-enough ECC to tame it.