The lifespan of a USB flash drive relates to three factors. In general terms, a flash drive will last much longer than you think and here are some details to help you understand the answer.
The three factors related to the life span of a USB flash drive are:
- How the drive is made
- Wear leveling technology
- How the drive is treated
Flash drives are a commodity product and (generally) driven by lowest price. With that in mind there are plenty of shortcuts a manufacturer can use to save time and money. What is important to understand, is knowing the quality of product you are going to use.
How the drive is made
A flash drive is made up of five primary components: The PCB (printed circuit board) the flash memory, the USB controller, the components and the soldering which holds everything together.
Printed Circuit Board (PCB)
Most promotional memory products (flash drives given away at trade shows) will use a two layer printed circuit board. Two layer boards are bad for use with any USB device, including a flash drive. The USB specification requires four layers for a product to be made to specification. A four layer board will include the, much needed, grounding plane of the PCB to insure transmission without interference from the trace lines. A two layer board is at a much greater risk of not performing as it should. If you received a USB at a trade show, don’t consider that device for “long term” or “important” storage options.
This is an image of a four layer USB flash drive by Nexcopy with Micron memory with write speeds of 12MB/s
Flash memory used in the production of USB drives stems from a sea of unknown factors. Flash drives are the bottom of the barrel when it comes to NAND memory as part of the BOM (bill of material). All the good quality NAND memory is used for more expensive products like phones, set-top boxes, communications hardware, etc… and the manufacturer of USB flash drives, is typically, the last tier of manufacturing consumption. With that in mind, one trick the flash manufacturers use, is down-sizing the memory wafer (NAND chip). Let us provide an example: Toshiba is the world’s largest memory manufacturer, and after production of say a 64GB chip, they test it. If the quality of the silicon cells in the chip are below a certain percentage, the chip gets downgraded to a 32GB chip. They test it. If the memory is still failing QC, it gets downgraded again. The process continues. So if you are dealing with a 512MB USB stick, you are dealing with the worst part of NAND memory chip. Very unreliable. The quickest way to test the quality of flash memory is test the write speed. For USB 2.0 product, if you see a write speed of 9-10MB/second or better… its’ good quality. For USB 3.0 if you see a write speed of 18-20MB/second or better you are dealing with good quality. A slow write speed means the silicon of the chip is having a harder time making the phase change (positive or negative) to save data to the memory chip.
The USB controller is the chip on the flash drive with all the brains. The USB controller is the gate keeper between the host computer and the USB stick. The chip allows the host computer to read or write data to and from the flash memory on the flash drive. Because the USB controller is the brain of the flash drive, it’s important to have a controller that performs well and is reliable. One of the most important features of the USB controller is wear leveling. This is also one of the most important aspects for defining the lifespan of a USB flash drive. More about wear leveling in a bit. For now, the important point is understanding the compatibility of the USB controller to that of the flash memory. The NAND memory market is very fast pasted. New technology is always developing. For this reason, the firmware inside the USB controller is very important. The firmware “marries” the flash memory to the device and creates a usable flash drive. There are many flavors of firmware for a single controller and it all boils down to how often the USB manufacturer updates those firmware tools. It is very possible to load firmware that is not optimized for the NAND memory used in the production of the flash drive. It’s also very possible the firmware is set for a different objective, for example, the firmware was set to be optimized for capacity rather than read/write speeds. The amount of control the USB factory has with these firmware tools is mind-blowing. The firmware tools are used to configure the USB stick to exactly what they want. In summary, there is no real way to test the quality of the USB controller and it’s firmware other than having an intimate knowledge and relationship with the actual manufacturer of the USB flash drive. The point to explaining the function of a USB controller is to show what a large impact it has on the overall performance of the drive.Continue Reading