Some links and info:
PC Mag says:
Core 2 isn’t just another iteration of the Pentium M. Instead, it steals a little from the old Netburst (Intel’s name for the architecture of the Pentium 4/Pentium D processors) architecture and adds additional enhancements of its own.
The result is a processor with a substantially shorter instruction pipeline than Netburst. The overall instructions executed per clock cycle is substantially higher, so even though Core 2 processors run at a lower clock frequency than previous Intel desktop lines, it runs applications faster. Core 2 is also more power efficient; Intel’s goal for the mainstream CPU is to maintain 65 W, versus the 90 to -95 W of the mainstream Pentium D’s, or the 130 W of the high-end Pentium D 940 or Extreme Edition CPUs.
Intel’s Core 2 Extreme X6800 didn’t lose a single benchmark in our comparison; not a single one. In many cases, the $183 Core 2 Duo E6300 actually outperformed Intel’s previous champ: the Pentium Extreme Edition 965. In one day, Intel has made its entire Pentium D lineup of processors obsolete. Intel’s Core 2 processors offer the sort of next-generation micro-architecture performance leap that we honestly haven’t seen from Intel since the introduction of the P6.
After years of wandering in the wilderness, Intel has recaptured the desktop CPU performance title in dramatic fashion. Both the Core 2 Extreme X6800 and the Core 2 Duo E6700 easily outperform the Athlon 64 FX-62 across a range of applications—and the E6600 is right in the hunt, as well. Not only that, but the Core 2 processors showed no real weaknesses in our performance tests.