According to Intel's latest plans the Nehalem iteration called Bloomfield should last at least until the end of Q1 2010. We are talking roughly one year from today and we are still not sure that even then Intel will rush to replace quad-core CPUs with six core CPUs.

The main issue will be the performance gain, as we believe that clock to clock Nehalem and Westmere based CPU would have a significant performance difference. Westmere will have a few new instructions and innovations over Nehalem / Bloomfield, but unless it runs at much higher clock, it won't make much of a difference in performance.

Computer games and most applications today, including your browser, simply won't benefit from six cores. In the server world you already have six core Core 2 based CPUs and there will be a Nehalem based upgrade this year, with more than four cores.