The PC is changing. Many common tasks (video game graphics, video encoding, etc.) benefit greatly from parallel processing. While some of this is addressed through multi-core processors, the graphics card vendors have been working in this space for a long time with single cards providing hundreds of pipelines. Companies like Nvidia have made no secret that they believe their technology will quickly displace the CPU as the heart of the PC architecture. Gizmodo has a nice article on these general-purpose GPUs.