You're right concerning CPUs but don't forget that AmigaOS is a light OS that is fast without the need of having a Xcores CPU and 50Gb RAM .... Amiga OS 4 run better than windows VISTA / 7 on the same computer specs ... Try to run windows 7 on a 633Mhz computer with a radeon 9200 and compare with the actual Sam440EP boards ... You'll see that AmigaOS4 is more responding than Windows VISTA/7
More to this you have a programmable custom chip XMOS that can handle 8 thread in real-time and can get access to memory, CPU, PCI, etc ...
In fact, it is the way to another "way of coding" ... instead of simply using multi-core ... you'll have a programmable device that can be used for various things ...