We tested the SSDs after 100TB of writes and again after 200TB, and they were pretty much as fast as they were fresh out of the box. The differences between our original scores and the results after 200TB work out to 2% or less:
You may recall that the HyperX drives were much faster in the random read test after 22TB than they were in a pristine state. Those higher scores persisted after 100TB, but after 200TB, performance has returned to the same levels we measured initially.
We can also track how fast Anvil's endurance benchmark runs on each drive. The endurance test writes a series of files with random sizes until it hits a predefined limit. Those files are then deleted before the next stream of writes begins. Let's see how the average speed of each loop has changed since testing began.
First, a disclaimer. These drives are running simultaneously on a mix of 6Gbps and 3Gbps SATA ports connected to a pair of identical test systems. The HyperX drives are connected to 3Gbps ports, while the rest have 6Gbps connectivity. We're not interested in the relative differences between the SSDs; instead, we're curious about how each one's write speed changes over time.
Those spikes in the Kingston and Intel results correspond to the breaks we took at 22 and 100TB. We secure-erase all the SSDs before testing performance at each interval, and that makes the SandForce drives notably faster in their first endurance run of the next wave.
The Samsung 840 Pro speeds up after each secure erase, too, but its performance has been erratic overall. Although most of the SSDs maintain largely stable write speeds, the 840 Pro spikes frequently. This behavior goes back to our early endurance runs, so it's likely attributable to garbage collection and internal management routines rather than flash wear. That said, it's worth noting that the 840 Pro achieved higher peak speeds in earlier runs.
Although the 840 Series doesn't exhibit the run-to-run variance of its sibling, the TLC drive has slowed somewhat. Since write speeds began their slow decline immediately, the recent rash of bad blocks isn't to blame.
Interestingly, the Corsair Neutron GTX has actually gotten slightly faster since we kicked off our endurance test. The Neutron's write speeds have leveled off over the last 50TB, though.
So concludes the latest chapter in our SSD Endurance Experiment. Already, we've demonstrated that modern SSDs can absorb an awful lot of writes without suffering ill effects. The Samsung 840 Series is spitting out an increasing number of bad blocks, though. It will be interesting to see what happens over the next 100TB and beyond. Everything we've learned thus far suggests we'll be at this for a while.