AMD may be considered inferior in the eyes of an average pc user, but that is not true, it matches up and even surpasses intel and is much more cheaper.the more ram you have the faster your pc will boot, but make sure it dual channeled.
as for the copy of xp not sure if that will ,make a great deal of a difference with repect to speed, but you can try it and see!!
Dell Inspiron 9300
Intel Pentium M 1.73GHZ
128MB ATI Mobility Radeon x300
80GB Hard drive