The only PS3 that can’t play PS2 games is the 40GB PS3.
All of the PS3’s avaliable can play PS1 games.
The 20GB and 60GB PS3’s can play nearly all PS1 and PS2 games because of the Emotion Engine chip hardware.
The 80GB PS3 can play around 75%-80% of PS1 and PS2 games because it uses Software Emulation.
And as far as I know, you Cannot install backward compatibility with PS2 games on the 40GB PS3 by just installing software. Sony made the 40GB PS3 unable to play PS2 games.








