It should be the same as your Windows, x86.

>When installing SQL Server 2005 Developer Edition on XP Professional SP2 which choice should I use:
>
>The choices in the set up are:
>x86-based Operating System
>x64-based Operating System
>Itanium-based OS
>
>Here are the spec of my pc:
>
>Latitude D820, Intel Core Duo T2500, 2.00GHz, 667Mhz, 2M L2 Cache, Dual Core (222-1263)
>
>Thank you in advance for your help.