Manufacturer's P/E rating assumes no recovery period between writes. If you allow for a recovery period, though, the write durability can be increased by quite a bit. Here's a paper on it, I think this was posted much earlier in the thread, but even if it was it's worth reposting.Originally Posted by Meo
With a recovery period of about 100 seconds they observed a 10-fold increase in write endurance for 2-bit 50nm MLC. With a recovery period of 3-4 hours, you're looking at a 100-fold increase in write endurance (so MLC NAND that's rated for 10k P/E cycles would be able to handle closer to 1 million).
This is something to keep in mind when looking at how long these drives being tested last. All the drives here are being written to very aggressively, so there will be less of a recovery period. In theory, under a more modest desktop workload where the drives aren't being written to as rapidly, you could expect even greater write endurance than the results in this thread suggest.
For example, during testing the NAND in the 64GB Samsung 470 was being overwritten once every 115 seconds or so. That isn't a very long recovery period, based on the durability increase for 50nm MLC in the study, you could expect roughly a 9.3x increase in endurance over the manufacturer's rating. The 34nm NAND is rated for 5k, which means it should be able to handle about 46.5k P/E cycles in practice. This seems to agree reasonably well with where the drive actually died (about 39k P/E cycles). Smaller geometry NAND probably benefits less from the same recovery period, which could be why endurance ended up being lower.
Also I think I've mentioned this before, but just wanted to say thanks again to all those sacrificing their time and money to make this possible. This thread is a wealth of knowledge, lots of great information here on real world write endurance and SSDs in general.