>>> All X86 processors require some companion chipset.

>> http://en.wikipedia.org/wiki/Vortex86 does not.

> Interesting. Missed that one, but then I don't think a
> single core i586 would be all that powerful.

There's also this since April 2012:
http://en.wikipedia.org/wiki/Atom_(system_on_chip)

Compared to Power Architecture SoCs, those Atom SoCs seem to lack things like SATA and Ethernet, but then they have 2D+3D GPU.