If this book can be used as a basis, then both of them started developing soon after the launch of the 360 and the PS3.
For the ones who haven't read it, Sony stared developing PS3 in 2001, and Microsoft started with the 360 in 2003, using similar architecture of the PowerPC core in Cell's chip, which was being created by IBM.
For the ones who haven't read it, Sony stared developing PS3 in 2001, and Microsoft started with the 360 in 2003, using similar architecture of the PowerPC core in Cell's chip, which was being created by IBM.