Beware: I tested a pair of Crucial "M4" SSDs (128GB & 256GB) and merely inserting one into my PowerMac G5 tower results in a kernel panic on boot.
I tried with the drive unformatted, and with it pre-formatted (Apple Partition Map, for PowerPC compatibility) and the kernel panic happens both ways.
I'm not sure why these drives don't get along with the G5; maybe because they are 6Gb/s?