Is it ever necessary to defragment a flash drive?

Answer 1

On a regular (non-solid-state) hard drive, defragmenting speeds up access by rearranging the hard drive's "blocks" such that all files are contiguous - usually when the file is created, it is allocated a series of contiguous blocks, but when the file gets modified, it may not be possible for it to utilize the blocks just after the ones occupied by what used to be the end of the file. Having all parts of the file together as much as possible means that the drive can read the file quicker and doesn't need to stop and start as often.

A flash drive has no moving parts, and it is often said that because of this a flash drive will see no benefit from being defragmented - there are no physical heads to move, only memory addresses. While this may be true in theory, this does not mean that there is NEVER any slowdown due to fragmentation on flash drives. This is the reason why Microsoft's ReadyBoost technology does not work with all flash drives - ReadyBoost flash drives are made with memory which is guaranteed to have a consistent access time for all memory locations, within a certain margin of error. The system uses this to guarantee that it can write to this drive within a certain amount of time, and that the write operation will actually be faster than a write to a regular hard drive. On other flash drives, there can be a difference in the time it takes to read a file that isn't fragmented and the time it takes to read a file that is fragmented.

Flash drives do have a limited number of reads and writes, but this is a "per-cell" limit, not a "per-drive" limit; is a "write cycle" limit, meaning that you won't be able to write to that area of memory once it wears out but will still be able to read from it; and is a minimum limit, meaning that it's guaranteed that all memory cells will withstand at least this many write operations. The limit is around 10,000 for a standard flash drive, and around 100,000 for a higher-quality flash drive. If you use your flash drive and write to it about 2-3 times a day every single day, in about 10 years it'll be broken to the point that you can't write to it, at which point you would copy all of your data to a new flash drive.

For the record - hard drives also have a limit, even if it is much higher. The difference is that defragmenting the hard drive also can minimize wear-and-tear on the drive, whereas with the flash drive it causes more wear-and-tear.

You don't ever "need" to defrag a flash drive. But if you notice that it has slowed down and is now unbearable, you might want to defrag it. Remember, though - defragging as often as you defrag a hard drive isn't going to be very helpful. Defrag it once every 3 months AT MOST - or if you don't care about speed at all and just want to get the longest life out of it, don't ever defrag it.

But most of all, keep in mind that if you have something on your flash drive that you just can't bear to lose, you should have a backup. Chances are that if the flash drive itself fails before you replace it, it's due to an error in the manufacturing process, which is something you can't really predict. Seeing as the whole point of these drives is portability, there's also the possibility that you'll unknowingly plug it into a virus-ridden computer, or that you'll lose the drive or break it by accident.

To summarize - there is a benefit to defragmenting a flash drive, although it is not nearly as noticeable as the performance benefit of defragmenting a regular drive, and defragmenting a flash drive (or any solid-state drive) will use up some of its write cycles which lowers its life just a little. The number of write cycles for the flash drive is limited, but is high enough that you shouldn't be too worried to defrag it if it's running unbearably slow.