SSDs emulate HDDs such that the operating system thinks it is talking to a hard drive. However the physical data mapping is quite different. In fact the SSD intelligently manages the physical location of data on the drive in the background via wear leveling algorithms that maximize the life of the SSD. The extremely fast access times of SSDs permit the SSD to move the data around as needed for wear leveling without impacting the performance. The net result is that defragmenting is not needed and defragmenting will not improve the performance. In fact, defragmentation should be turned off.
All of these SSDs benefit from the Microsoft Windows 7 TRIM command. The TRIM command is focused on maintaining MLC SSD write performance by erasing no longer used (released) logical blocks (aka files deleted from the Windows recycle bin) from the SSD automatically in the background. Note that TRIM is not supported with SSDs in a RAID array.