Just found the following article on eweek: Oracle Caves on Multicore licensing.
A core is only 0.75 times a cpu:
Licensing terms for the Oracle Store Web site now state that, for the purposes of counting how many processors need to be licensed, a multicore chip with “n” cores will be multiplied by 0.75. Oracle will then round up fractions to the next whole number.
July 19th, 2005 at 13:01:13
[...] rtunately that was to late to pick up an entry about [...]