Originally Posted by hermitmaster
I would say my primary concern is reliability, then speed. I use my PC for work, school, and gaming. I'd hate to lose all of my data in between backups, and I've read that TLC nand isn't quite as reliable as MLC.
Technically true, but if you're writing 10GB a day on average or less (creating and editing files, paging file for hibernating and/or if you don't have any RAM) it will last a very long time. 10GB a day for the smaller drives (which have the same number of write cycles but only a fourth or eighth the capacity) will last a good portion of the decade or more, at which point they'll be obsolete anyway.
Basically, a bit is determined by an electron either being trapped or absent in a level of the cell. If an electron becomes "stuck" in one level, then the cell becomes read-only. TLC gives an additional chance for electrons to get stuck vs. MLC which, although exponentially decreasing lifespan, is still not much for a typical consumer. Also remember that when MLC drives started to hit the market, people were concerned about lifespan and speeds too, but now MLC is the standard for consumers. Some concern is understandable, since MLC can only handle around a tenth the writes of equivalent SLC, but that tenth still numbers in the thousands. Also, when the drives get smaller, they are more likely to fail since each individual NAND gate is less durable. 2xnm can withstand about twice as many writes as 1xnm, for example. Shrinking NAND is more of an issue than SLC vs. MLC vs. TLC (vs. QLC vs. PLC...).
BUT! Samsung has done an excellent job making their TLC drives durable.
The 840 EVO's TLC portion is rated at 2500 P/E cycles and the SLC buffer at 50 000 P/E cycles (P/E is program erase, or the entire drive being written to 2500 and 50 000 times, respectively). That's what Samsung has rated it for, however, it is 1) going to survive far longer than most/all HDDs under the same strain, and 2) will likely survive past 2500 cycles anyway since that 2500 is a minimum guarantee of 100% drive health. Just be sure to enable TRIM, disable hibernate, shrink the paging file to 512MiB or less, disable anything that ends in "-fetch," and DISABLE DISK DEFRAG THAT WILL KILL YOUR DRIVE.