[MegaMan X]

found this on another forum talking about tweaks on another forum

1) Disable Adaptive Hot File Clustering

This is a feature of the OS that tracks how often files are used and automatically moves them closer to the outer rim of the drive (which is faster on conventional disks). On an SSD it is just a useless block move.

2) Disable automatic defrag

This actually might not be a win, because the system only performs auto defrag in very limited cases (files less than >20 megs with more than 8 extents), and while defragging the file itself will not be a performance win, consolidating its metadata into the file record (so you don't have to walk through the extents btree) might in fact be a win even on an SSD because it significantly reduces the amount of reads you have to do figure out where the file is.

The unfortunate thing is that there is no simple way to do either of these. You could build a custom kernel (it is a ~1-2 line change to short circuit them out). I suspect that neither is going to be a particularly large win though, so you are better off just running a stock (supported) kernel.

Mac OSX Speed Tweaks - OCZ Forum

If I had a Mac to try these on, I would only attempt the one on page 6 by kmess (post 88) and also disable SMS (the motion sensor for mechanical hard drives) myself.

On page 4, Azu does mention that no tweaks are necessary for an X25-M (but I would still apply/try the two above).

Note that OS/X does not give you a means of disabling its auto defrag routine (at least not while using the shipping official 'core')- this is something that is still not addressed in snowkitty, maybe a point update will enable it (at least for SSD's).