FWIW, early designs for the PS3 also were missing the GPU in lieu of another Cell chip. The end of Dennard scaling meant that they didn't hit the clock speed they originally intended (close to 5Ghz). It was originally supposed to do rasterization in software on that second cell, but relatively in the last minute they needed to strap a dedicated GPU to it. That's why Cell reads out of VRAM are incredibly slow, around 16MB/s.