Designing a decent CPUs without violating any patents is easy. Almost all CPUs today follow design patterns which were established back in the mid 80s and early 90s. All those original patents have now expired and you can sidestep around the newer ones.
Things like GPUs have evolved massively since the late 90s, gaining support for pixel shaders, vertex shaders, moving to unified core designs, gpu compute and establishing new threading models.
And all these things have bled back into the Graphics standards. It would be really hard to design a gpu implementing even a 10 year old standard like OpenGL ES 2.0 without violating any patents.
And it will be even worse with things like pci-e, ddr and networking controllers. You can't design around the patents without breaking compatibility because there are standards enforcing you to follow the patents.