best amd athlon dual core cpu for overclocking

[Penny_7]

my uncle wants me to build him a windows xp pc so he can play his old games from 1998 to 2005. and he wants to overclock the cpu, he has settled on either an athlon 64 X2 dual core or an athlon 2 dual core

what i want to know is whats the best cpu in the athlon 64 X2 and athlon 2 dual core line that can get him to a stable 4Ghz on a decent cooler

he has everything but the cpu so what cpu is best also make sure its a black edtion or at least that its multiplier is unlocked

 

[CountMike]

Athlon II x2 (if on compatible AM2+ MB) with Regor core is unlocked and can be OCed pretty good because of low power requirements. I had my 270 up to 4.2 GHz.