Dell Latitude D630 is a thin and lightweight version of the Latitude line. With a 14.1 LCD screen and a 9 cell battery, this laptop is meant to be more mobile.
This model was manufactured for several years with different clock speeds. The earliest D630s were 1.8GHz, gradually increased to 2.0, 2.2 and finally 2.5. I've run both the 2.0 and 2.5GHz versions and there is a noticeable difference in performance.
2