While the Duron 1.6Ghz is entering the shops, the 1800 dlt3c is leaving them. Nowadays it's more difficult to find an Athlon XP with the "magical" code "DLT3C".
If you want to buy a really cheap CPU and don't mind the few percentage drop in performance then I would recommend buying the new Duron Applebred. It is a fair overclocker and using higher voltages and good cooling it has even more headroom!
But if you are after every last extra performance increase, stick with the Ahtlon XP which sports amasing overclocking potential (If you can lay your hands on the JIUHB DLT3C ones), good overall performance and a very competitive price!
Del med dine venner