The most common question to have when considering NAND flash storage is, “How long will this drive last?” This is a very valid question in trying to understand whether single-level cell (SLC) or multiple-level cell (MLC) NAND flash is necessary as well as what capacity will be sufficient. Although it is known that there is a direct relationship between capacity and useful life, answering the original question requires some explanation.
Pattern of Usage
There are many reasons why it is challenging to make an apples-to-apples comparison of drives, especially from two different manufacturers. The reason being that the three factors that determine the actual useful life of a solid state drive are the device’s technology (controller, flash, and firmware), capacity, and usage model (i.e., amount and size of data being written), all three of which vary even within a single manufacturer’s storage line. The device’s technology has the most direct relationship to flash cell lifetime. The way these factors (technology, capacity, and usage model) come together determines a pattern of usage for the drive, which is unique for every system and is the key reason that it is so difficult to perfectly predict a drive’s useful life.
Even though a user can identify what their drive's technology, capacity, and usage model are, there will always be a significant disparity between how much information users think they are writing versus how much is actually being written. Again, this is because the way these three factors come together create the pattern of usage, which is unique to every system and makes it impossible to know how all the information is managed over time. Due to this, even when these three factors are clearly identified, the useful life prediction is hypothetical.
With all these factors at play, the most accurate way to know how long a given flash drive will work in a specific usage environment is to perform a field test. While it is up to the user to determine if the upfront investment is worth the cost, we highly encourage that adequate thought and consideration be invested. If a field test is not a viable option, we also provide a comparison tool that will help in discerning the type of NAND flash and capacity needed. Remember that SLC NAND flash will always outlast MLC NAND flash as its cells can tolerate 100,000 program/erase cycles, whereas MLC can tolerate between 5,000 to 10,000 program/erase cycles. Users can also be confident of Emphase drive lifetimes due to the 5-year warranty that comes standard on all devices.
> Do a quick comparison of different devices in a controlled usage scenario
> Learn how to perform a field test factoring in actual usage and performance data