The number of drives on your system, for the most part will not slow your system down. Without knowing your CPU speed as well as your CPU Type, Bus Speed and TSR's it is difficult to diagnose the problem. Defrag is a good idea. I would definately use the smaller drive as my primary drive (with O.S.). Only the drive with the Operating system will be active for most of the work. You have plenty of memory, but I am not sure of the memory type (probobly SDRam), however, if you are currently having serious slowing that you never had before, I smell a virus. Viruses running in the background can slow down the fastest of computers. Upgrade youe Anti Virus, and scan the drives.