As such, its 8MB Level 2 cache is not completely shareable between all four cores. Rather, it's split into two separate 4MB caches, each of which is shareable between their respective core pairs.
According to Intel, we will not see a true quad-core (four cores on a die) processor until the second half of this year. Codenamed Yorkfield, it will debut in the new 45nm process and come with a fully-shared 8MB L2 cache."
Full report at http://www.techarp.com/showarticle.aspx?artno=379