Cell used the PowerPC isa as did the Xbox 360. Both were designed in the same IBM facility but separated by a floor. IIRC the Xbox team indirectly learned from the Cell team's mistakes at the process/microarch level.

Cell was definitely more weird to code against and Sony put max theoretical perf above Xbox's approach to be more general purpose chip architecture. So strictly speaking it wasn't like most PCs at the time in the x86 sense but in the three mostly same cores for Xbox vs custom Cell and special ways to squeeze out performance.