Quad Processor Intel Mac?
MacBidouille posts some screenshots which claim to demonstrate an unreleased Quad Processor Intel-based PowerMac with Hyperthreading support.
Without giving much details, those captures shows MacOSX x86 running on a 4 physical CPU-based MacIntel with Hyperthreading enable. One can clearly see 4 physical processors recognized while 8 logical processors are recorded by the CPU monitor. So MacOSX can really manage without problem any MacIntel based on either physical or logical processors.