Originally Posted by gca3020
No need to walk on eggshells, of course, so don't worry about adding/removing files, getting new books, etc... but while defragging would move some files around, you won't see any performance increase (in fact, there's a good chance any performance change would be negative, or completely negligible.)
Not to be a downer on everyone who thinks defragging offers no performance gains on the Kindle, but I have seen firsthand that it helps wonders (in my case).
Here's my story. I got a Kindle 3 with 3G. I got a bunch of books. I put loads of books on it. I analyzed it with a defrag program just because I was curious, and it was pretty fragmented. I didn't defrag it. I took lots of notes and highlighted lots of things. I added collections to make things more accessible. It was getting slower and slower the more I added books and especially the more I highlighted and took notes. It would freeze for long periods (and sometimes until I powered off/on) when I took notes in certain ways. I lived with it. Eventually, however, my Kindle sort of crashed and when I powered on and off this time all my books were in the wrong order and no matter what I did, it would never put the most recent book first (it put it in some random location near the end of my list). This, of course, was highly annoying.
I thought about doing a firmware upgrade and thought maybe that would fix the issue (I don't know if I need a firmware upgrade), but I have dialup and the upgrade won't come through the 3G (and it's like 22MB or something, which would likely be interrupted by a phone call knocking me off and forcing me to start over). So, I decided to see if defragmenting it would help.
I defragmented my Kindle (before realizing that it was supposed to be more risky to defrag flash memory) with Smart Defrag (the portableapps version). Then, I tried it out. It was like 37% fragmented or something. So, about 40 minutes later, it was done. I tried my Kindle and it was good as new. It was as fast it had been before I put any books on it (which is to say about 20 times faster). The sorting bug-thing was even fixed (I had hoped for that, but honestly, I can't seem to make sense out of why it helped; I'm pretty sure it's not just because I connected it to the computer and changed the drive's contents, though). My files were still in the wrong order they had been, but viewing them put them up top again, is what I mean.
Anyway, there are definite performance gains, even if there are risks. Don't believe anyone who tells you otherwise.
Of course, fragmentation is going to occur if you copy lots of small files onto a Kindle. Files don't always come unfragmented when they're freshly copied. That's actually one of the things that can cause fragmentation.
If you put hundreds or thousands of books on your Kindle, and especially if you use notes and marks a lot, then you might appreciate this. If you only have like 30 books, don't mark things, and have no huge PDF files, then you'll probably be fine forever without something like this.