The PS3 could do general purpose computing. Its built in operating system let you play games, watch movies, play music, browse the web, etc. At the beginning of the console's life you could even install Linux on it.
The hardware of consoles has been general purpose for decades.
The current and previous generations of xbox and playstation do use x86 CPUs with integrated AMD GPUs. But they aren't just PCs in a small box. Using a unified pool of GDDR memory* is a substantial architectural difference.
*except for the xbox one & one s, which had its own weird setup with unified DDR3 and a programmer controlled ESRAM cache.
