WHEN WERE THE AMALEKITES SLAIN?

I Samuel 15:7  And Saul smote the Amalekites from Havilah until thou comest to Shur, that is over against Egypt. (KJV) I Samuel 27:8-9  And David and his men went up, and invaded the Geshurites, and the Gezrites, and the Amalekites: for those nations were of old the inhabitants of the land, as thou goest to Shur, even unto the land of Egypt.  And David smote the land, and left neither man nor woman alive, and took away the sheep, and the oxen, and the asses, and the camels, and the apparel, and returned, and came to Achish. (KJV) I Samuel 30:1  And it came to pass, when David and his men were come to Ziklag on the third day, that the Amalekites had invaded the south, and Ziklag, and smitten Ziklag, and burned it with fire; (KJV) I Samuel 30:17  And David smote them from the twilight even unto the evening of the next day: and there escaped not a man of them, save four hundred young men, which rode upon camels, and fled. (KJV)

In each case, it's talking about Amalekite soldiers or camps, not the entire Amalekite race.  Not a contradiction.