We benchmarked all the SSDs before we began our endurance experiment, and we've gathered more performance data after every 100TB of writes since. It's important to note that these tests are far from exhaustive. Our in-depth SSD reviews are a much better resource for comparative performance data. What we're looking for here is how each SSD's benchmark scores change as the writes add up.
For the most part, all the drives have performed consistently since we began. We've observed a few blips here and there, including a potential one for the Neutron GTX in the last sequential read speed test. The drive hit roughly the same speed through five runs, so it was consistent in that sense, just short of previous efforts. We'll have to see what happens at 1.1PB and beyond.
Accumulated writes don't affect performance in most of these tests. However, the read speeds on the Samsung 840 Series are a little slower in our last set of results. Hmmm. Perhaps our other performance data will be more enlightening.
Unlike our first batch of results, which was obtained on the same system after secure-erasing each drive, the next set comes from the endurance test itself. Anvil's utility lets us calculate the write speed of each loop that loads the drives with random data. This test runs simultaneously on six drives split between two separate systems (and between 3Gbps SATA ports for the HyperX drives and 6Gbps ones for the others), so the data isn't useful for apples-to-apples comparisons. However, it does provide a long-term look at how each drive handles this particular write workload.
Again, the SSDs have mostly behaved consistently. The 840 Pro's run-to-run inconsistency is kind of its thing, while the Neutron GTX's slowly increasing pace has been evident from the start. Pay no attention to the regular spikes for some of the SSDs; those are related to the secure erase we perform before running our performance benchmarks every 100TB.
Our casualties maintained consistent write speeds for much of their lives, but there's evidence of sputtering toward the end. Let's zoom in for a closer look. The Intel and Kingston SSDs are covered through their final runs, but we don't have data for the Samsung beyond 900TB.
Even without its last gasps on record, the 840 Series clearly started breathing more erratically over the last few hundred terabytes. The HyperX barely staggered in its final steps, while the 335 Series suffered a short but noticeable bout of wheezing before it hit the wall.
Ok, so maybe that's a stretch—the noticeable bit, not the drawn-out running metaphor. These are ultimately minor reductions in write speeds, at least for the Intel and Kingston SSDs. It's possible the Samsung got substantially slower closer to the end of its life, though I wouldn't bet on it based on the data we have.