The average consumer doesn't have to worry about this at all (mainly because the new model of PS3 doesn't have back compatibility).
It has been officially confirmed that the Play Station 4 will not support Play Station 3 games natively. disc-based) or digitally downloaded games from the Playstation Network will not be playable on the new console due to the x86 architecture.
In a roundtable with journalists after the Play Station 4 reveal, Sony's Shuhei Yoshida, President of Sony Worldwide Studios, elaborated further on the question of backwards compatibility.
Couldn't fimd a console gaming topic so I chose other consumer electronics.
Bought a used one of these off Ebay from original owner that rarely used it.
It doesn’t work.” Based off of statements made at Sony's PS4 reveal event, it is believed that Sony will be using Gaikai's capabilities to provide access to games from previous Play Station consoles through Gaikai's cloud streaming capabilities. At this point, it is not known whether this will require players to re-purchase games they already own, although this seems quite likely.
Gaikai streaming is reportedly going to be available in the later half of 2014.
The earliest PS3 model was backwards compatible with PS2, and it is a much requested feature... On balance, we are happy with our approach and we don't wish to be defensive about it at all.
But as I say, both approaches are legitimate."(Also see: Sony's E3 2015 Conference: The Last Guardian, Final Fantasy VII Remake, Shenmue 3, and More)While it might seem understandable, this approach serves to benefit its Play Station Now game streaming service, which lets PS4 owners access limited PS3 titles for a fee.
Speaking to games industry website MCV, Play Station Europe's Jim Ryan confirmed this.