According to reports (or just perhaps rumours) coming out of Intel Developer Forum (IDF), Intel's next major architectural update to the Core 2 will be Yorkfield, a true quad-core design.

Although true quad means having all four execution engines on same piece of silicon connected with the same L2 cache, the reality of any performance gains over the Kentsfield are unlikely to be substantial. Getting sufficient raw performance out of 4 processors as to show the difference between what a quad and what is essentially a pair of duals would require a feat of programming genius.

Furthermore, Yorkfield fits nicely into Intel's transition to 45nm fabrication, and while that means a 70% reduction in size, a 45nm quad core would still be 40% larger than a 65nm dual core, meaning increased costs and yield issues.

It's much more likely this move is part of an 8-core initiative.