if it's a power5 then i'd assume that the CPUs are dual core... but it's not like windows systems where a dual core processor will be viewed as two processors to the OS.

i don't know oracle's licensing policies, but from other software that i've dealt with, noone deals with the number of cores a processor has... most only deal with how many processors the OS sees. so in your case, 3 processors (looks like it's a 3 proc LPAR).

you may need to ask oracle about how it deals with the P-series/AIX capacity on demand issues, LPARs, and micro partitioning.