These days everyone is talking about SSD or Solid state drives. SSD is much faster than Platter Hard Disk, silent and much more efficient. On The same time they complicated to maintain as well. Not All OS support the TRIM or Garbage Collection which is basically responsible for optimum usage of speed and Performance they have. If you purchased a SSD and you install it with and OS which does not support either of these you won’t be able to see significant performance improvement. and More time you keep your Computer On performance will keep coming down making it at par with IDE or SATA drive.
Most of SSD supports TRIM and not garbage Collection and at present only WIndows7 and Windows 2008 support this so Essentially if you plan to use any of these 2 OS with your SSD then only you should purchase it. But Question is how to measure the performance ?