There is a very interesting story breaking today concerning AMD processors and a new "proof-of-concept" virus. It seems the virus can gain low-level access to hardware and potentially bypass kernel and user-level protection mechanisms. Dubbed W32.Bounds (32-bit) and W64.Bounds (64-bit), the virus is not much of a threat at the moment, as you can see in the threat assessment posted at Symantec.
"The worm comes in two versions, targeting 32-bit and 64-bit processors from AMD. Symantec refers to the online pests as w32.bounds and w64.bounds. Because it involves proof of concept code, both viruses are rated as low level threats. Although at this point it concerns harmless proof of concept code, the virus could be used as a starting point to create malware that affects computers with disparate operating systems"